Merge pull request #3425 from jepler/canbus

canio: Initial implementation for SAM E5x MCUs

40 files changed, 2963 insertions, 40 deletions

diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 37212e241..c9114dd5c 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2020-09-16 17:07-0700\n"
+"POT-Creation-Date: 2020-09-21 16:45-0500\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -92,7 +92,11 @@ msgstr ""
 msgid "%q must be a tuple of length 2"
 msgstr ""
 
-#: ports/atmel-samd/common-hal/sdioio/SDCard.c
+#: shared-bindings/canio/Match.c
+msgid "%q out of range"
+msgstr ""
+
+#: ports/atmel-samd/common-hal/microcontroller/Pin.c
 msgid "%q pin invalid"
 msgstr ""
 
@@ -280,6 +284,10 @@ msgstr ""
 msgid "All I2C peripherals are in use"
 msgstr ""
 
+#: ports/atmel-samd/common-hal/canio/Listener.c
+msgid "All RX FIFOs in use"
+msgstr ""
+
 #: ports/nrf/common-hal/busio/SPI.c
 msgid "All SPI peripherals are in use"
 msgstr ""
@@ -316,6 +324,10 @@ msgstr ""
 msgid "Already advertising."
 msgstr ""
 
+#: ports/atmel-samd/common-hal/canio/Listener.c
+msgid "Already have all-matches listener"
+msgstr ""
+
 #: shared-module/memorymonitor/AllocationAlarm.c
 #: shared-module/memorymonitor/AllocationSize.c
 msgid "Already running"
@@ -752,7 +764,7 @@ msgstr ""
 msgid "Error in regex"
 msgstr ""
 
-#: shared-bindings/_bleio/__init__.c shared-bindings/aesio/aes.c
+#: py/enum.c shared-bindings/_bleio/__init__.c shared-bindings/aesio/aes.c
 #: shared-bindings/busio/SPI.c shared-bindings/microcontroller/Pin.c
 #: shared-bindings/neopixel_write/__init__.c
 #: shared-bindings/terminalio/Terminal.c
@@ -845,6 +857,10 @@ msgstr ""
 msgid "File exists"
 msgstr ""
 
+#: ports/atmel-samd/common-hal/canio/Listener.c
+msgid "Filters too complex"
+msgstr ""
+
 #: ports/cxd56/common-hal/camera/Camera.c
 msgid "Format not supported"
 msgstr ""
@@ -1127,6 +1143,10 @@ msgstr ""
 msgid "Maximum x value when mirrored is %d"
 msgstr ""
 
+#: shared-bindings/canio/Message.c
+msgid "Messages limited to 8 bytes"
+msgstr ""
+
 #: supervisor/shared/safe_mode.c
 msgid "MicroPython NLR jump failed. Likely memory corruption."
 msgstr ""
@@ -2310,6 +2330,10 @@ msgstr ""
 msgid "exceptions must derive from BaseException"
 msgstr ""
 
+#: shared-bindings/canio/CAN.c shared-bindings/canio/Listener.c
+msgid "expected '%q' but got '%q'"
+msgstr ""
+
 #: py/objstr.c
 msgid "expected ':' after format specifier"
 msgstr ""
@@ -3147,6 +3171,10 @@ msgstr ""
 msgid "source palette too large"
 msgstr ""
 
+#: shared-bindings/canio/Message.c
+msgid "specify size or data, but not both"
+msgstr ""
+
 #: py/objstr.c
 msgid "start/end indices"
 msgstr ""
@@ -3261,7 +3289,7 @@ msgid "tuple/list has wrong length"
 msgstr ""
 
 #: ports/atmel-samd/common-hal/busio/UART.c ports/nrf/common-hal/busio/UART.c
-#: shared-bindings/busio/UART.c
+#: shared-bindings/busio/UART.c shared-bindings/canio/CAN.c
 msgid "tx and rx cannot both be None"
 msgstr ""
 
diff --git a/main.c b/main.c
index 5b719dc4b..dbd367a59 100755
--- a/main.c
+++ b/main.c
@@ -81,6 +81,10 @@
 #include "supervisor/shared/bluetooth.h"
 #endif
 
+#if CIRCUITPY_CANIO
+#include "common-hal/canio/CAN.h"
+#endif
+
 void do_str(const char *src, mp_parse_input_kind_t input_kind) {
     mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, src, strlen(src), 0);
     if (lex == NULL) {
@@ -226,6 +230,10 @@ void cleanup_after_vm(supervisor_allocation* heap) {
     free_memory(heap);
     supervisor_move_memory();
 
+    #if CIRCUITPY_CANIO
+    common_hal_canio_reset();
+    #endif
+
     reset_port();
     #if CIRCUITPY_BOARD
     reset_board_busses();
diff --git a/ports/atmel-samd/Makefile b/ports/atmel-samd/Makefile
index aba630dbb..1ee21679d 100644
--- a/ports/atmel-samd/Makefile
+++ b/ports/atmel-samd/Makefile
@@ -393,6 +393,10 @@ SRC_QSTR += $(HEADER_BUILD)/sdiodata.h
 $(HEADER_BUILD)/sdiodata.h: tools/mksdiodata.py | $(HEADER_BUILD)
 	$(Q)$(PYTHON3) $< > $@
 
+SRC_QSTR += $(HEADER_BUILD)/candata.h
+$(HEADER_BUILD)/candata.h: tools/mkcandata.py | $(HEADER_BUILD)
+	$(Q)$(PYTHON3) $< > $@
+
 SRC_QSTR += $(SRC_C) $(SRC_SUPERVISOR) $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED)
 # Sources that only hold QSTRs after pre-processing.
 SRC_QSTR_PREPROCESSOR += peripherals/samd/$(PERIPHERALS_CHIP_FAMILY)/clocks.c
diff --git a/ports/atmel-samd/asf4_conf/same51/peripheral_clk_config.h b/ports/atmel-samd/asf4_conf/same51/peripheral_clk_config.h
index 59fe8730e..51173f6d3 100644
--- a/ports/atmel-samd/asf4_conf/same51/peripheral_clk_config.h
+++ b/ports/atmel-samd/asf4_conf/same51/peripheral_clk_config.h
@@ -1165,6 +1165,88 @@
 #define CONF_SDHC1_SLOW_FREQUENCY 12000000
 #endif
 
+// <h> CAN Clock Settings
+// <y> CAN Clock source
+
+// <GCLK_PCHCTRL_GEN_GCLK0_Val"> Generic clock generator 0
+
+// <GCLK_PCHCTRL_GEN_GCLK1_Val"> Generic clock generator 1
+
+// <GCLK_PCHCTRL_GEN_GCLK2_Val"> Generic clock generator 2
+
+// <GCLK_PCHCTRL_GEN_GCLK3_Val"> Generic clock generator 3
+
+// <GCLK_PCHCTRL_GEN_GCLK4_Val"> Generic clock generator 4
+
+// <GCLK_PCHCTRL_GEN_GCLK5_Val"> Generic clock generator 5
+
+// <GCLK_PCHCTRL_GEN_GCLK6_Val"> Generic clock generator 6
+
+// <GCLK_PCHCTRL_GEN_GCLK7_Val"> Generic clock generator 7
+
+// <GCLK_PCHCTRL_GEN_GCLK8_Val"> Generic clock generator 8
+
+// <GCLK_PCHCTRL_GEN_GCLK9_Val"> Generic clock generator 9
+
+// <GCLK_PCHCTRL_GEN_GCLK10_Val"> Generic clock generator 10
+
+// <GCLK_PCHCTRL_GEN_GCLK11_Val"> Generic clock generator 11
+
+// <i> Select the clock source for CAN.
+// <id> sdhc_gclk_selection
+#ifndef CONF_GCLK_CAN0_SRC
+#define CONF_GCLK_CAN0_SRC GCLK_PCHCTRL_GEN_GCLK0_Val
+#endif
+
+/**
+ * \def CAN FREQUENCY
+ * \brief CAN's Clock frequency
+ */
+#ifndef CONF_CAN0_FREQUENCY
+#define CONF_CAN0_FREQUENCY 120000000
+#endif
+
+// <h> CAN Clock Settings
+// <y> CAN Clock source
+
+// <GCLK_PCHCTRL_GEN_GCLK0_Val"> Generic clock generator 0
+
+// <GCLK_PCHCTRL_GEN_GCLK1_Val"> Generic clock generator 1
+
+// <GCLK_PCHCTRL_GEN_GCLK2_Val"> Generic clock generator 2
+
+// <GCLK_PCHCTRL_GEN_GCLK3_Val"> Generic clock generator 3
+
+// <GCLK_PCHCTRL_GEN_GCLK4_Val"> Generic clock generator 4
+
+// <GCLK_PCHCTRL_GEN_GCLK5_Val"> Generic clock generator 5
+
+// <GCLK_PCHCTRL_GEN_GCLK6_Val"> Generic clock generator 6
+
+// <GCLK_PCHCTRL_GEN_GCLK7_Val"> Generic clock generator 7
+
+// <GCLK_PCHCTRL_GEN_GCLK8_Val"> Generic clock generator 8
+
+// <GCLK_PCHCTRL_GEN_GCLK9_Val"> Generic clock generator 9
+
+// <GCLK_PCHCTRL_GEN_GCLK10_Val"> Generic clock generator 10
+
+// <GCLK_PCHCTRL_GEN_GCLK11_Val"> Generic clock generator 11
+
+// <i> Select the clock source for CAN.
+// <id> sdhc_gclk_selection
+#ifndef CONF_GCLK_CAN1_SRC
+#define CONF_GCLK_CAN1_SRC GCLK_PCHCTRL_GEN_GCLK0_Val
+#endif
+
+/**
+ * \def CAN FREQUENCY
+ * \brief CAN's Clock frequency
+ */
+#ifndef CONF_CAN1_FREQUENCY
+#define CONF_CAN1_FREQUENCY 120000000
+#endif
+
 // <<< end of configuration section >>>
 
 #endif // PERIPHERAL_CLK_CONFIG_H
diff --git a/ports/atmel-samd/asf4_conf/same54/peripheral_clk_config.h b/ports/atmel-samd/asf4_conf/same54/peripheral_clk_config.h
index 59fe8730e..51173f6d3 100644
--- a/ports/atmel-samd/asf4_conf/same54/peripheral_clk_config.h
+++ b/ports/atmel-samd/asf4_conf/same54/peripheral_clk_config.h
@@ -1165,6 +1165,88 @@
 #define CONF_SDHC1_SLOW_FREQUENCY 12000000
 #endif
 
+// <h> CAN Clock Settings
+// <y> CAN Clock source
+
+// <GCLK_PCHCTRL_GEN_GCLK0_Val"> Generic clock generator 0
+
+// <GCLK_PCHCTRL_GEN_GCLK1_Val"> Generic clock generator 1
+
+// <GCLK_PCHCTRL_GEN_GCLK2_Val"> Generic clock generator 2
+
+// <GCLK_PCHCTRL_GEN_GCLK3_Val"> Generic clock generator 3
+
+// <GCLK_PCHCTRL_GEN_GCLK4_Val"> Generic clock generator 4
+
+// <GCLK_PCHCTRL_GEN_GCLK5_Val"> Generic clock generator 5
+
+// <GCLK_PCHCTRL_GEN_GCLK6_Val"> Generic clock generator 6
+
+// <GCLK_PCHCTRL_GEN_GCLK7_Val"> Generic clock generator 7
+
+// <GCLK_PCHCTRL_GEN_GCLK8_Val"> Generic clock generator 8
+
+// <GCLK_PCHCTRL_GEN_GCLK9_Val"> Generic clock generator 9
+
+// <GCLK_PCHCTRL_GEN_GCLK10_Val"> Generic clock generator 10
+
+// <GCLK_PCHCTRL_GEN_GCLK11_Val"> Generic clock generator 11
+
+// <i> Select the clock source for CAN.
+// <id> sdhc_gclk_selection
+#ifndef CONF_GCLK_CAN0_SRC
+#define CONF_GCLK_CAN0_SRC GCLK_PCHCTRL_GEN_GCLK0_Val
+#endif
+
+/**
+ * \def CAN FREQUENCY
+ * \brief CAN's Clock frequency
+ */
+#ifndef CONF_CAN0_FREQUENCY
+#define CONF_CAN0_FREQUENCY 120000000
+#endif
+
+// <h> CAN Clock Settings
+// <y> CAN Clock source
+
+// <GCLK_PCHCTRL_GEN_GCLK0_Val"> Generic clock generator 0
+
+// <GCLK_PCHCTRL_GEN_GCLK1_Val"> Generic clock generator 1
+
+// <GCLK_PCHCTRL_GEN_GCLK2_Val"> Generic clock generator 2
+
+// <GCLK_PCHCTRL_GEN_GCLK3_Val"> Generic clock generator 3
+
+// <GCLK_PCHCTRL_GEN_GCLK4_Val"> Generic clock generator 4
+
+// <GCLK_PCHCTRL_GEN_GCLK5_Val"> Generic clock generator 5
+
+// <GCLK_PCHCTRL_GEN_GCLK6_Val"> Generic clock generator 6
+
+// <GCLK_PCHCTRL_GEN_GCLK7_Val"> Generic clock generator 7
+
+// <GCLK_PCHCTRL_GEN_GCLK8_Val"> Generic clock generator 8
+
+// <GCLK_PCHCTRL_GEN_GCLK9_Val"> Generic clock generator 9
+
+// <GCLK_PCHCTRL_GEN_GCLK10_Val"> Generic clock generator 10
+
+// <GCLK_PCHCTRL_GEN_GCLK11_Val"> Generic clock generator 11
+
+// <i> Select the clock source for CAN.
+// <id> sdhc_gclk_selection
+#ifndef CONF_GCLK_CAN1_SRC
+#define CONF_GCLK_CAN1_SRC GCLK_PCHCTRL_GEN_GCLK0_Val
+#endif
+
+/**
+ * \def CAN FREQUENCY
+ * \brief CAN's Clock frequency
+ */
+#ifndef CONF_CAN1_FREQUENCY
+#define CONF_CAN1_FREQUENCY 120000000
+#endif
+
 // <<< end of configuration section >>>
 
 #endif // PERIPHERAL_CLK_CONFIG_H
diff --git a/ports/atmel-samd/boards/common.template.ld b/ports/atmel-samd/boards/common.template.ld
index 1054605c8..53c4cf5ee 100644
--- a/ports/atmel-samd/boards/common.template.ld
+++ b/ports/atmel-samd/boards/common.template.ld
@@ -43,6 +43,15 @@ SECTIONS
         _sidata = .;       /* start of .data section */
     } >FLASH_FIRMWARE
 
+    /* Data accessed by the CAN peripheral must be in the first 64kB RAM */
+    /* place it at the very start of RAM, before the .data section */
+    /* it is zeroed by reset_port */
+    .canram (NOLOAD) :
+    {
+        . = ALIGN(4);
+        *(.canram)
+    } > RAM
+
     /* This is the initialized data section
     The program executes knowing that the data is in the RAM
     but the loader puts the initial values in the FLASH_FIRMWARE (inidata).
@@ -61,7 +70,7 @@ SECTIONS
     } >RAM
 
     /* Uninitialized data section */
-    .bss :
+    .bss (NOLOAD) :
     {
         . = ALIGN(4);
         _sbss = .;
diff --git a/ports/atmel-samd/boards/feather_m4_can/mpconfigboard.mk b/ports/atmel-samd/boards/feather_m4_can/mpconfigboard.mk
index 306e7fe42..345ac33c5 100644
--- a/ports/atmel-samd/boards/feather_m4_can/mpconfigboard.mk
+++ b/ports/atmel-samd/boards/feather_m4_can/mpconfigboard.mk
@@ -12,3 +12,4 @@ EXTERNAL_FLASH_DEVICES = GD25Q16C
 LONGINT_IMPL = MPZ
 
 CIRCUITPY_VECTORIO = 1
+CIRCUITPY_CANIO = 1
diff --git a/ports/atmel-samd/boards/same54_xplained/mpconfigboard.mk b/ports/atmel-samd/boards/same54_xplained/mpconfigboard.mk
index 7ac126514..e4472e05d 100644
--- a/ports/atmel-samd/boards/same54_xplained/mpconfigboard.mk
+++ b/ports/atmel-samd/boards/same54_xplained/mpconfigboard.mk
@@ -12,3 +12,4 @@ EXTERNAL_FLASH_DEVICES = "N25Q256A"
 LONGINT_IMPL = MPZ
 
 CIRCUITPY_SDIOIO = 1
+CIRCUITPY_CANIO = 1
diff --git a/ports/atmel-samd/boards/same54_xplained/pins.c b/ports/atmel-samd/boards/same54_xplained/pins.c
index 8a864ab97..1ed431fba 100644
--- a/ports/atmel-samd/boards/same54_xplained/pins.c
+++ b/ports/atmel-samd/boards/same54_xplained/pins.c
@@ -48,8 +48,9 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
 
     { MP_OBJ_NEW_QSTR(MP_QSTR_QT),  MP_ROM_PTR(&pin_PA16) },
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_CANRX),  MP_ROM_PTR(&pin_PB12) },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_CANTX),  MP_ROM_PTR(&pin_PB13) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_CAN_RX),  MP_ROM_PTR(&pin_PB13) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_CAN_TX),  MP_ROM_PTR(&pin_PB12) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_CAN_STANDBY),  MP_ROM_PTR(&pin_PC13) },
 
     // EXT1 header
     { MP_OBJ_NEW_QSTR(MP_QSTR_PB04),  MP_ROM_PTR(&pin_PB04) },
diff --git a/ports/atmel-samd/common-hal/canio/CAN.c b/ports/atmel-samd/common-hal/canio/CAN.c
new file mode 100644
index 000000000..4f28698fb
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/CAN.c
@@ -0,0 +1,445 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "py/runtime.h"
+#include "py/mperrno.h"
+
+#include "peripheral_clk_config.h"
+
+#include "common-hal/canio/CAN.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/util.h"
+#include "supervisor/port.h"
+
+#include "component/can.h"
+
+#include "genhdr/candata.h"
+
+STATIC Can * const can_insts[] = CAN_INSTS;
+
+STATIC canio_can_obj_t *can_objs[MP_ARRAY_SIZE(can_insts)];
+
+// This must be placed in the first 64kB of RAM
+STATIC COMPILER_SECTION(".canram") canio_can_state_t can_state[MP_ARRAY_SIZE(can_insts)];
+
+void common_hal_canio_can_construct(canio_can_obj_t *self, mcu_pin_obj_t *tx, mcu_pin_obj_t *rx, int baudrate, bool loopback, bool silent)
+{
+    mcu_pin_function_t *tx_function = mcu_find_pin_function(can_tx, tx, -1, MP_QSTR_tx);
+    int instance = tx_function->instance;
+
+    mcu_pin_function_t *rx_function = mcu_find_pin_function(can_rx, rx, instance, MP_QSTR_rx);
+
+    const uint32_t can_frequency = CONF_CAN0_FREQUENCY;
+
+#define DIV_ROUND(a, b) (((a) + (b)/2) / (b))
+#define DIV_ROUND_UP(a, b) (((a) + (b) - 1) / (b))
+
+    uint32_t clocks_per_bit = DIV_ROUND(can_frequency, baudrate);
+    uint32_t clocks_to_sample = DIV_ROUND(clocks_per_bit * 7, 8);
+    uint32_t clocks_after_sample = clocks_per_bit - clocks_to_sample;
+    uint32_t divisor = MAX(DIV_ROUND_UP(clocks_to_sample, 256), DIV_ROUND_UP(clocks_after_sample, 128));
+    if (divisor > 32) {
+        mp_raise_OSError(MP_EINVAL); // baudrate cannot be attained (16kHz or something is lower bound, should never happen)
+    }
+
+    gpio_set_pin_direction(tx_function->pin, GPIO_DIRECTION_OUT);
+    gpio_set_pin_function(tx_function->pin, tx_function->function);
+    common_hal_never_reset_pin(tx_function->obj);
+
+    gpio_set_pin_direction(rx_function->pin, GPIO_DIRECTION_IN);
+    gpio_set_pin_function(rx_function->pin, rx_function->function);
+    common_hal_never_reset_pin(rx_function->obj);
+
+    self->tx_pin_number = tx ? common_hal_mcu_pin_number(tx) : COMMON_HAL_MCU_NO_PIN;
+    self->rx_pin_number = rx ? common_hal_mcu_pin_number(rx) : COMMON_HAL_MCU_NO_PIN;
+    self->hw = can_insts[instance];
+    self->state = &can_state[instance];
+
+    self->loopback = loopback;
+    self->silent = silent;
+
+    // Allow configuration change
+    hri_can_set_CCCR_INIT_bit(self->hw);
+    while (hri_can_get_CCCR_INIT_bit(self->hw) == 0) {
+    }
+    hri_can_set_CCCR_CCE_bit(self->hw);
+
+    if (instance == 0) {
+        hri_mclk_set_AHBMASK_CAN0_bit(MCLK);
+        hri_gclk_write_PCHCTRL_reg(GCLK, CAN0_GCLK_ID, CONF_GCLK_CAN0_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
+
+        NVIC_DisableIRQ(CAN0_IRQn);
+        NVIC_ClearPendingIRQ(CAN0_IRQn);
+        NVIC_EnableIRQ(CAN0_IRQn);
+        hri_can_write_ILE_reg(self->hw, CAN_ILE_EINT0);
+#ifdef CAN1_GCLK_ID
+    } else if (instance == 1) {
+        hri_mclk_set_AHBMASK_CAN1_bit(MCLK);
+        hri_gclk_write_PCHCTRL_reg(GCLK, CAN1_GCLK_ID, CONF_GCLK_CAN1_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
+
+        NVIC_DisableIRQ(CAN1_IRQn);
+        NVIC_ClearPendingIRQ(CAN1_IRQn);
+        NVIC_EnableIRQ(CAN1_IRQn);
+        hri_can_write_ILE_reg(self->hw, CAN_ILE_EINT0);
+#endif
+    }
+
+    self->hw->CCCR.bit.FDOE = 0; // neither FD nor Bit Rate Switch enabled
+    self->hw->CCCR.bit.BRSE = 0;
+
+    hri_can_write_MRCFG_reg(self->hw, CAN_MRCFG_QOS(CAN_MRCFG_QOS_DISABLE_Val)); // QoS disabled (no sensitive operation)
+
+    // A "nominal bit" is a header bit.  With dual rate CAN FD, this is a slower rate
+    {
+        CAN_NBTP_Type btp = {
+            // 0 means "1 tq", but 2 is subtracted from NTSEG1 for the
+            // fixed 1 "SYNC" tq
+            .bit.NTSEG1 = DIV_ROUND(clocks_to_sample, divisor) - 2,
+            .bit.NTSEG2 = DIV_ROUND(clocks_after_sample, divisor) - 1,
+            .bit.NBRP = divisor - 1,
+            .bit.NSJW = DIV_ROUND(clocks_after_sample, divisor * 4),
+        };
+        hri_can_write_NBTP_reg(self->hw, btp.reg);
+    }
+
+    // A "data bit" is a data bit :) with dula rate CAN FD, this is a higher
+    // rate.  However, CAN FD is not implemented in CircuitPython, and this is
+    // the same rate as the "nominal rate".
+    {
+        CAN_DBTP_Type btp = {
+            .bit.DTSEG1 = DIV_ROUND(clocks_to_sample, divisor) - 1,
+            .bit.DTSEG2 = DIV_ROUND(clocks_after_sample, divisor) - 1,
+            .bit.DBRP = divisor - 1,
+            .bit.DSJW = DIV_ROUND(clocks_after_sample, divisor * 4),
+        };
+        hri_can_write_DBTP_reg(self->hw, btp.reg);
+    }
+
+    {
+        CAN_RXF0C_Type rxf = {
+            .bit.F0SA = (uint32_t)self->state->rx0_fifo,
+            .bit.F0S = COMMON_HAL_CANIO_RX_FIFO_SIZE,
+        };
+        hri_can_write_RXF0C_reg(self->hw, rxf.reg);
+    }
+
+    {
+        CAN_RXF1C_Type rxf = {
+            .bit.F1SA = (uint32_t)self->state->rx1_fifo,
+            .bit.F1S = COMMON_HAL_CANIO_RX_FIFO_SIZE,
+        };
+        hri_can_write_RXF1C_reg(self->hw, rxf.reg);
+    }
+
+    // All RX data has an 8 byte payload (max)
+    {
+        CAN_RXESC_Type esc = {
+            .bit.F0DS = CAN_RXESC_F0DS_DATA8_Val,
+            .bit.F1DS = CAN_RXESC_F1DS_DATA8_Val,
+            .bit.RBDS = CAN_RXESC_RBDS_DATA8_Val,
+        };
+        hri_can_write_RXESC_reg(self->hw, esc.reg);
+    }
+
+    // All TX data has an 8 byte payload (max)
+    {
+        CAN_TXESC_Type esc = {
+            .bit.TBDS = CAN_TXESC_TBDS_DATA8_Val,
+        };
+        hri_can_write_TXESC_reg(self->hw, esc.reg);
+    }
+
+    {
+        CAN_TXBC_Type bc = {
+            .bit.TBSA = (uint32_t)self->state->tx_buffer,
+            .bit.NDTB = COMMON_HAL_CANIO_TX_FIFO_SIZE,
+            .bit.TFQM = 0, // Messages are transmitted in the order submitted
+        };
+        hri_can_write_TXBC_reg(self->hw, bc.reg);
+    }
+
+    {
+        CAN_TXEFC_Type efc = {
+            .bit.EFS = 0,
+        };
+        hri_can_write_TXEFC_reg(self->hw, efc.reg);
+    }
+
+    {
+        CAN_GFC_Type gfc = {
+            .bit.RRFE = 0,
+            .bit.ANFS = CAN_GFC_ANFS_REJECT_Val,
+            .bit.ANFE = CAN_GFC_ANFE_REJECT_Val,
+        };
+        hri_can_write_GFC_reg(self->hw, gfc.reg);
+    }
+
+    {
+        CAN_SIDFC_Type dfc = {
+            .bit.LSS = COMMON_HAL_CANIO_RX_FILTER_SIZE,
+            .bit.FLSSA = (uint32_t)self->state->standard_rx_filter
+        };
+        hri_can_write_SIDFC_reg(self->hw, dfc.reg);
+    }
+
+    {
+        CAN_XIDFC_Type dfc = {
+            .bit.LSE = COMMON_HAL_CANIO_RX_FILTER_SIZE,
+            .bit.FLESA = (uint32_t)self->state->extended_rx_filter
+        };
+        hri_can_write_XIDFC_reg(self->hw, dfc.reg);
+    }
+
+    {
+        CAN_IE_Type ie = {
+            .bit.EWE = 1,
+            .bit.EPE = 1,
+            .bit.BOE = 1,
+        };
+        hri_can_write_IE_reg(self->hw, ie.reg);
+    }
+
+    hri_can_write_XIDAM_reg(self->hw, CAN_XIDAM_RESETVALUE);
+
+// silent: The CAN is set in Bus Monitoring Mode by programming CCCR.MON to '1'. (tx pin unused)
+// external loopback: The CAN can be set in External Loop Back Mode by programming TEST.LBCK and CCCR.MON to '1'. (rx pin unused)
+// internal loopback (silent loopback): Internal Loop Back Mode is entered by programming bits TEST.LBCK and CCCR.MON to '1'. (tx, rx unused)
+    self->hw->CCCR.bit.MON = silent;
+    self->hw->CCCR.bit.TEST = loopback;
+    self->hw->TEST.bit.LBCK = loopback;
+
+    if (instance == 0) {
+        NVIC_DisableIRQ(CAN0_IRQn);
+        NVIC_ClearPendingIRQ(CAN0_IRQn);
+        NVIC_EnableIRQ(CAN0_IRQn);
+#ifdef CAN1_GCLK_ID
+    } else if (instance == 1) {
+        NVIC_DisableIRQ(CAN1_IRQn);
+        NVIC_ClearPendingIRQ(CAN1_IRQn);
+        NVIC_EnableIRQ(CAN1_IRQn);
+#endif
+    }
+
+    hri_can_write_ILE_reg(self->hw, CAN_ILE_EINT0);
+    // Prevent configuration change
+    hri_can_clear_CCCR_CCE_bit(self->hw);
+    hri_can_clear_CCCR_INIT_bit(self->hw);
+    while (hri_can_get_CCCR_INIT_bit(self->hw)) {
+    }
+
+    can_objs[instance] = self;
+}
+
+bool common_hal_canio_can_loopback_get(canio_can_obj_t *self)
+{
+    return self->loopback;
+}
+
+int common_hal_canio_can_baudrate_get(canio_can_obj_t *self)
+{
+    return self->baudrate;
+}
+
+int common_hal_canio_can_transmit_error_count_get(canio_can_obj_t *self)
+{
+    return self->hw->ECR.bit.TEC;
+}
+
+int common_hal_canio_can_receive_error_count_get(canio_can_obj_t *self)
+{
+    return self->hw->ECR.bit.REC;
+}
+
+int common_hal_canio_can_error_warning_state_count_get(canio_can_obj_t *self)
+{
+    return self->error_warning_state_count;
+}
+
+int common_hal_canio_can_error_passive_state_count_get(canio_can_obj_t *self)
+{
+    return self->error_passive_state_count;
+}
+
+int common_hal_canio_can_bus_off_state_count_get(canio_can_obj_t *self)
+{
+    return self->bus_off_state_count;
+}
+
+canio_bus_state_t common_hal_canio_can_state_get(canio_can_obj_t *self) {
+    CAN_PSR_Type psr = self->hw->PSR;
+    if (psr.bit.BO) {
+        return BUS_STATE_OFF;
+    }
+    if (psr.bit.EP) {
+        return BUS_STATE_ERROR_PASSIVE;
+    }
+    if (psr.bit.EW) {
+        return BUS_STATE_ERROR_WARNING;
+    }
+    return BUS_STATE_ERROR_ACTIVE;
+}
+
+void common_hal_canio_can_restart(canio_can_obj_t *self) {
+    if (!self->hw->PSR.bit.BO) {
+        return;
+    }
+
+    hri_can_clear_CCCR_INIT_bit(self->hw);
+    while (hri_can_get_CCCR_INIT_bit(self->hw)) {
+    }
+}
+
+bool common_hal_canio_can_auto_restart_get(canio_can_obj_t *self) {
+    return self->auto_restart;
+}
+
+void common_hal_canio_can_auto_restart_set(canio_can_obj_t *self, bool value) {
+    self->auto_restart = value;
+}
+
+static void maybe_auto_restart(canio_can_obj_t *self) {
+    if (self->auto_restart) {
+        common_hal_canio_can_restart(self);
+    }
+}
+
+void common_hal_canio_can_send(canio_can_obj_t *self, canio_message_obj_t *message)
+{
+    maybe_auto_restart(self);
+
+    // We have just one dedicated TX buffer, use it!
+    canio_can_tx_buffer_t *ent = &self->state->tx_buffer[0];
+
+    ent->txb0.bit.ESI = false;
+    ent->txb0.bit.XTD = message->extended;
+    ent->txb0.bit.RTR = message->rtr;
+    if (message->extended) {
+        ent->txb0.bit.ID = message->id;
+    } else {
+        ent->txb0.bit.ID = message->id << 18; // short addresses are left-justified
+    }
+
+    ent->txb1.bit.MM = 0; // "message marker"
+    ent->txb1.bit.EFC = 0; // don't store fifo events to event queue
+    ent->txb1.bit.FDF = 0; // Classic CAN format
+    ent->txb1.bit.BRS = 0; // No bit rate switching
+    ent->txb1.bit.DLC = message->size;
+
+    if (!message->rtr) {
+        memcpy(ent->data, message->data, message->size);
+    }
+
+    // TX buffer add request
+    self->hw->TXBAR.reg = 1;
+
+    // wait 8ms (hard coded for now) for TX to occur
+    uint64_t deadline = port_get_raw_ticks(NULL) + 8;
+    while (port_get_raw_ticks(NULL) < deadline && !(self->hw->TXBTO.reg & 1)) {
+        RUN_BACKGROUND_TASKS;
+    }
+}
+
+bool common_hal_canio_can_silent_get(canio_can_obj_t *self) {
+    return self->silent;
+}
+
+bool common_hal_canio_can_deinited(canio_can_obj_t *self) {
+    return !self->hw;
+}
+
+void common_hal_canio_can_check_for_deinit(canio_can_obj_t *self) {
+    if (common_hal_canio_can_deinited(self)) {
+        raise_deinited_error();
+    }
+}
+
+void common_hal_canio_can_deinit(canio_can_obj_t *self)
+{
+    if (self->hw) {
+        hri_can_set_CCCR_INIT_bit(self->hw);
+        self->hw = 0;
+    }
+    if (self->rx_pin_number != COMMON_HAL_MCU_NO_PIN) {
+        reset_pin_number(self->rx_pin_number);
+        self->rx_pin_number = COMMON_HAL_MCU_NO_PIN;
+    }
+    if (self->tx_pin_number != COMMON_HAL_MCU_NO_PIN) {
+        reset_pin_number(self->tx_pin_number);
+        self->tx_pin_number = COMMON_HAL_MCU_NO_PIN;
+    }
+}
+
+void common_hal_canio_reset(void) {
+    memset(can_state, 0, sizeof(can_state));
+
+    for (size_t i=0; i<MP_ARRAY_SIZE(can_insts); i++) {
+        hri_can_set_CCCR_INIT_bit(can_insts[i]);
+    }
+
+    for (size_t i=0; i<MP_ARRAY_SIZE(can_objs); i++) {
+        if (can_objs[i]) {
+            common_hal_canio_can_deinit(can_objs[i]);
+            can_objs[i] = NULL;
+        }
+    }
+}
+
+
+STATIC void can_handler(int i) {
+    canio_can_obj_t *self = can_objs[i];
+    (void) self;
+
+    Can *hw = can_insts[i];
+    uint32_t ir = hri_can_read_IR_reg(hw);
+
+    /* Count up errors*/
+    if (ir & CAN_IE_EWE) {
+        self->error_warning_state_count += 1;
+    }
+    if (ir & CAN_IE_EPE) {
+        self->error_passive_state_count += 1;
+    }
+    if (ir & CAN_IE_BOE) {
+        self->bus_off_state_count += 1;
+    }
+
+    /* Acknowledge interrupt */
+    hri_can_write_IR_reg(hw, ir);
+}
+
+__attribute__((used))
+void CAN0_Handler(void) {
+    can_handler(0);
+}
+
+#ifdef CAN1_GCLK_ID
+__attribute__((used))
+void CAN1_Handler(void) {
+    can_handler(1);
+}
+#endif
diff --git a/ports/atmel-samd/common-hal/canio/CAN.h b/ports/atmel-samd/common-hal/canio/CAN.h
new file mode 100644
index 000000000..cdea60e7d
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/CAN.h
@@ -0,0 +1,55 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-bindings/canio/__init__.h"
+#include "shared-bindings/canio/CAN.h"
+#include "component/can.h"
+#include "common-hal/microcontroller/Pin.h"
+#include "common-hal/canio/__init__.h"
+#include "shared-module/canio/Message.h"
+
+#define COMMON_HAL_CAN_RX_FIFO_LEN (2)
+#define COMMON_HAL_CAN_TX_FIFO_LEN (2)
+
+typedef struct canio_can_obj {
+    mp_obj_base_t base;
+    Can *hw;
+    canio_can_state_t *state;
+    volatile uint32_t error_warning_state_count;
+    volatile uint32_t error_passive_state_count;
+    volatile uint32_t bus_off_state_count;
+    int baudrate;
+    uint8_t rx_pin_number:8;
+    uint8_t tx_pin_number:8;
+    bool loopback:1;
+    bool silent:1;
+    bool auto_restart:1;
+    bool fifo0_in_use:1;
+    bool fifo1_in_use:1;
+} canio_can_obj_t;
diff --git a/ports/atmel-samd/common-hal/canio/Listener.c b/ports/atmel-samd/common-hal/canio/Listener.c
new file mode 100644
index 000000000..02cfde9cc
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/Listener.c
@@ -0,0 +1,391 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <math.h>
+#include <string.h>
+
+#include "py/obj.h"
+#include "py/runtime.h"
+
+#include "common-hal/canio/__init__.h"
+#include "common-hal/canio/Listener.h"
+#include "shared-bindings/util.h"
+#include "supervisor/shared/tick.h"
+#include "component/can.h"
+
+STATIC void allow_config_change(canio_can_obj_t *can) {
+    can->hw->CCCR.bit.INIT = 1;
+    while (!can->hw->CCCR.bit.INIT) {
+    }
+    can->hw->CCCR.bit.CCE = 1;
+}
+
+STATIC void prevent_config_change(canio_can_obj_t *can) {
+    can->hw->CCCR.bit.CCE = 0;
+    can->hw->CCCR.bit.INIT = 0;
+    while (can->hw->CCCR.bit.INIT) {
+    }
+}
+
+__attribute__((unused))
+STATIC void static_assertions(void) {
+    MP_STATIC_ASSERT(CAN_GFC_ANFE_RXF0_Val + 1 == CAN_GFC_ANFE_RXF1_Val);
+    MP_STATIC_ASSERT(CAN_GFC_ANFS_RXF0_Val + 1 == CAN_GFC_ANFS_RXF1_Val);
+    MP_STATIC_ASSERT(CAN_SIDFE_0_SFEC_STF0M_Val + 1 == CAN_SIDFE_0_SFEC_STF1M_Val);
+    MP_STATIC_ASSERT(CAN_XIDFE_0_EFEC_STF0M_Val + 1 == CAN_XIDFE_0_EFEC_STF1M_Val);
+}
+
+STATIC bool single_address_filter(canio_match_obj_t *match) {
+    return match->mask == 0 || match->mask == match->address;
+}
+
+STATIC bool standard_filter_in_use(CanMramSidfe *filter) {
+    return filter->SIDFE_0.bit.SFEC != CAN_SIDFE_0_SFEC_DISABLE_Val;
+}
+
+STATIC bool extended_filter_in_use(CanMramXidfe *filter) {
+    return filter->XIDFE_0.bit.EFEC != CAN_XIDFE_0_EFEC_DISABLE_Val;
+}
+
+STATIC size_t num_filters_needed(size_t nmatch, canio_match_obj_t **matches, bool extended) {
+    size_t num_half_filters_needed = 1;
+    for(size_t i=0; i<nmatch; i++) {
+        if (extended != matches[i]->extended) {
+            continue;
+        }
+        if (single_address_filter(matches[i])) {
+            num_half_filters_needed += 1;
+        } else {
+            num_half_filters_needed += 2;
+        }
+    }
+    return num_half_filters_needed / 2;
+}
+
+STATIC size_t num_filters_available(canio_can_obj_t *can, bool extended) {
+    size_t available = 0;
+    if (extended) {
+        for(size_t i = 0; i < MP_ARRAY_SIZE(can->state->extended_rx_filter); i++) {
+            if (!extended_filter_in_use(&can->state->extended_rx_filter[i])) {
+                available++;
+            }
+        }
+    } else {
+        for(size_t i = 0; i < MP_ARRAY_SIZE(can->state->standard_rx_filter); i++) {
+            if (!standard_filter_in_use(&can->state->standard_rx_filter[i])) {
+                available++;
+            }
+        }
+    }
+    return available;
+}
+
+STATIC void clear_filters(canio_listener_obj_t *self) {
+    canio_can_obj_t *can = self->can;
+    int fifo = self->fifo_idx;
+
+    // If it was a global accept, clear it
+    allow_config_change(can);
+    if (can->hw->GFC.bit.ANFS == CAN_GFC_ANFS_RXF0 + fifo) {
+        can->hw->GFC.bit.ANFS = CAN_GFC_ANFS_REJECT_Val;
+    }
+    if (can->hw->GFC.bit.ANFE == CAN_GFC_ANFE_RXF0 + fifo) {
+        can->hw->GFC.bit.ANFE = CAN_GFC_ANFE_REJECT_Val;
+    }
+    prevent_config_change(can);
+
+    // For each filter entry, if it pointed at this FIFO set it to DISABLE
+    for(size_t i = 0; i < MP_ARRAY_SIZE(can->state->extended_rx_filter); i++) {
+        int val = CAN_XIDFE_0_EFEC_STF0M_Val + fifo;
+        if (can->state->extended_rx_filter[i].XIDFE_0.bit.EFEC == val) {
+            can->state->extended_rx_filter[i].XIDFE_0.bit.EFEC = CAN_XIDFE_0_EFEC_DISABLE_Val;
+        }
+    }
+    for(size_t i = 0; i < MP_ARRAY_SIZE(can->state->standard_rx_filter); i++) {
+        int val = CAN_SIDFE_0_SFEC_STF1M_Val + fifo;
+        if (can->state->standard_rx_filter[i].SIDFE_0.bit.SFEC == val) {
+            can->state->standard_rx_filter[i].SIDFE_0.bit.SFEC = CAN_SIDFE_0_SFEC_DISABLE_Val;
+        }
+    }
+}
+
+STATIC CanMramXidfe *next_extended_filter(canio_listener_obj_t *self, CanMramXidfe *start) {
+    CanMramXidfe *end = &self->can->state->extended_rx_filter[MP_ARRAY_SIZE(self->can->state->extended_rx_filter)];
+    if (start == NULL) {
+        start = self->can->state->extended_rx_filter;
+    } else {
+        start = start + 1;
+    }
+    while (extended_filter_in_use(start)) {
+        if (start == end) {
+            return NULL;
+        }
+        start = start + 1;
+    }
+    return start;
+}
+
+STATIC CanMramSidfe *next_standard_filter(canio_listener_obj_t *self, CanMramSidfe *start) {
+    CanMramSidfe *end = &self->can->state->standard_rx_filter[MP_ARRAY_SIZE(self->can->state->standard_rx_filter)];
+    if (start == NULL) {
+        start = self->can->state->standard_rx_filter;
+    } else {
+        start = start + 1;
+    }
+    while (standard_filter_in_use(start)) {
+        if (start == end) {
+            return NULL;
+        }
+        start = start + 1;
+    }
+    return start;
+}
+
+STATIC void install_standard_filter(CanMramSidfe *standard, int id1, int id2, int sfec, int sft) {
+    assert(standard);
+    CAN_SIDFE_0_Type val = {
+        .bit.SFID1 = id1,
+        .bit.SFID2 = id2,
+        .bit.SFEC = sfec,
+        .bit.SFT = sft,
+    };
+    standard->SIDFE_0 = val;
+}
+
+STATIC void install_extended_filter(CanMramXidfe *extended, int id1, int id2, int efec, int eft) {
+    assert(extended);
+    CAN_XIDFE_0_Type val0 = {
+        .bit.EFID1 = id1,
+        .bit.EFEC = efec,
+    };
+    CAN_XIDFE_1_Type val1 = {
+        .bit.EFID2 = id2,
+        .bit.EFT = eft,
+    };
+    // Set entry 0 second, because it has the enable bits (XIDFE_0_EFEC)
+    extended->XIDFE_1 = val1;
+    extended->XIDFE_0 = val0;
+}
+
+
+#define NO_ADDRESS (-1)
+void set_filters(canio_listener_obj_t *self, size_t nmatch, canio_match_obj_t **matches) {
+    int fifo = self->fifo_idx;
+
+    if (!nmatch) {
+        allow_config_change(self->can);
+        self->can->hw->GFC.bit.ANFS = CAN_GFC_ANFS_RXF0_Val + fifo;
+        self->can->hw->GFC.bit.ANFE = CAN_GFC_ANFE_RXF0_Val + fifo;
+        self->can->hw->CCCR.bit.CCE = 0;
+        prevent_config_change(self->can);
+        return;
+    }
+
+    CanMramSidfe *standard = next_standard_filter(self, NULL);
+    CanMramXidfe *extended = next_extended_filter(self, NULL);
+
+    int first_address = NO_ADDRESS;
+
+    // step 1: single address standard matches
+    // we have to gather up pairs and stuff them in a single filter entry
+    for(size_t i = 0; i<nmatch; i++) {
+        canio_match_obj_t *match = matches[i];
+        if (match->extended) {
+            continue;
+        }
+        if (!single_address_filter(match)) {
+            continue;
+        }
+        if (first_address != NO_ADDRESS) {
+            install_standard_filter(standard, first_address, match->address, CAN_SIDFE_0_SFEC_STF0M_Val + fifo, CAN_SIDFE_0_SFT_DUAL_Val);
+            first_address = NO_ADDRESS;
+            standard = next_standard_filter(self, standard);
+        } else {
+            first_address = match->address;
+        }
+    }
+    // step 1.5. odd single address standard match
+    if (first_address != NO_ADDRESS) {
+            install_standard_filter(standard, first_address, first_address, CAN_SIDFE_0_SFEC_STF0M_Val + fifo, CAN_SIDFE_0_SFT_DUAL_Val);
+            standard = next_standard_filter(self, standard);
+            first_address = NO_ADDRESS;
+    }
+
+    // step 2: standard mask filter
+    for(size_t i = 0; i<nmatch; i++) {
+        canio_match_obj_t *match = matches[i];
+        if (match->extended) {
+            continue;
+        }
+        if (single_address_filter(match)) {
+            continue;
+        }
+        install_standard_filter(standard, match->address, match->mask, CAN_SIDFE_0_SFEC_STF0M_Val + fifo, CAN_SIDFE_0_SFT_CLASSIC_Val);
+        standard = next_standard_filter(self, standard);
+    }
+
+    // step 3: single address extended matches
+    // we have to gather up pairs and stuff them in a single filter entry
+    for(size_t i = 0; i<nmatch; i++) {
+        canio_match_obj_t *match = matches[i];
+        if (!match->extended) {
+            continue;
+        }
+        if (!single_address_filter(match)) {
+            continue;
+        }
+        if (first_address != NO_ADDRESS) {
+            install_extended_filter(extended, first_address, match->address, CAN_XIDFE_0_EFEC_STF0M_Val + fifo, CAN_XIDFE_1_EFT_DUAL_Val);
+            first_address = NO_ADDRESS;
+            extended = next_extended_filter(self, extended);
+        } else {
+            first_address = match->address;
+        }
+    }
+    // step 3.5. odd single address standard match
+    if (first_address != NO_ADDRESS) {
+            install_extended_filter(extended, first_address, first_address, CAN_XIDFE_0_EFEC_STF0M_Val + fifo, CAN_XIDFE_1_EFT_DUAL_Val);
+            extended = next_extended_filter(self, extended);
+            first_address = NO_ADDRESS;
+    }
+
+    // step 4: extended mask filters
+    for(size_t i = 0; i<nmatch; i++) {
+        canio_match_obj_t *match = matches[i];
+        if (!match->extended) {
+            continue;
+        }
+        if (single_address_filter(match)) {
+            continue;
+        }
+        install_extended_filter(extended, match->address, match->mask, CAN_XIDFE_0_EFEC_STF0M_Val + fifo, CAN_XIDFE_1_EFT_CLASSIC_Val);
+        extended = next_extended_filter(self, extended);
+    }
+
+    // phew, easy(!)
+}
+
+
+void common_hal_canio_listener_construct(canio_listener_obj_t *self, canio_can_obj_t *can, size_t nmatch, canio_match_obj_t **matches, float timeout) {
+    if (!can->fifo0_in_use) {
+        self->fifo_idx = 0;
+        self->fifo = can->state->rx0_fifo;
+        self->hw = (canio_rxfifo_reg_t*)&can->hw->RXF0C;
+        can->hw->IR.reg = CAN_IR_RF0N | CAN_IR_RF0W | CAN_IR_RF0F | CAN_IR_RF0L;
+        can->fifo0_in_use = true;
+    } else if (!can->fifo1_in_use) {
+        self->fifo_idx = 1;
+        self->fifo = can->state->rx1_fifo;
+        self->hw = (canio_rxfifo_reg_t*)&can->hw->RXF1C;
+        can->fifo1_in_use = true;
+        can->hw->IR.reg = CAN_IR_RF1N | CAN_IR_RF1W | CAN_IR_RF1F | CAN_IR_RF1L;
+    } else {
+        mp_raise_ValueError(translate("All RX FIFOs in use"));
+    }
+
+    if (!nmatch) {
+        if (can->hw->GFC.bit.ANFS == CAN_GFC_ANFS_RXF1_Val - self->fifo_idx) {
+            mp_raise_ValueError(translate("Already have all-matches listener"));
+        }
+        if (can->hw->GFC.bit.ANFE == CAN_GFC_ANFE_RXF1_Val - self->fifo_idx) {
+            mp_raise_ValueError(translate("Already have all-matches listener"));
+        }
+    }
+
+    if (num_filters_needed(nmatch, matches, false) > num_filters_available(can, false)) {
+        mp_raise_ValueError(translate("Filters too complex"));
+    }
+
+    if (num_filters_needed(nmatch, matches, true) > num_filters_available(can, true)) {
+        mp_raise_ValueError(translate("Filters too complex"));
+    }
+
+    // Nothing can fail now so it's safe to assign self->can
+    self->can = can;
+    set_filters(self, nmatch, matches);
+    common_hal_canio_listener_set_timeout(self, timeout);
+}
+
+void common_hal_canio_listener_set_timeout(canio_listener_obj_t *self, float timeout) {
+    self->timeout_ms = (int)MICROPY_FLOAT_C_FUN(ceil)(timeout * 1000);
+}
+
+float common_hal_canio_listener_get_timeout(canio_listener_obj_t *self) {
+    return self->timeout_ms / 1000.0f;
+}
+
+void common_hal_canio_listener_check_for_deinit(canio_listener_obj_t *self) {
+    if (!self->can) {
+        raise_deinited_error();
+    }
+    common_hal_canio_can_check_for_deinit(self->can);
+}
+
+int common_hal_canio_listener_in_waiting(canio_listener_obj_t *self) {
+    return self->hw->RXFS.bit.F0FL;
+}
+
+bool common_hal_canio_listener_readinto(canio_listener_obj_t *self, canio_message_obj_t *message) {
+    if (!common_hal_canio_listener_in_waiting(self)) {
+        uint64_t deadline = supervisor_ticks_ms64() + self->timeout_ms;
+        do {
+            if (supervisor_ticks_ms64() > deadline) {
+                return false;
+            }
+        } while (!common_hal_canio_listener_in_waiting(self));
+    }
+    int index = self->hw->RXFS.bit.F0GI;
+    canio_can_rx_fifo_t *hw_message = &self->fifo[index];
+    message->extended = hw_message->rxf0.bit.XTD;
+    if (message->extended) {
+        message->id = hw_message->rxf0.bit.ID;
+    } else {
+        message->id = hw_message->rxf0.bit.ID >> 18; // short addresses are left-justified
+    }
+    message->rtr = hw_message->rxf0.bit.RTR;
+    message->size = hw_message->rxf1.bit.DLC;
+    if (!message->rtr) {
+        memcpy(message->data, hw_message->data, message->size);
+    }
+    self->hw->RXFA.bit.F0AI = index;
+    return true;
+}
+
+void common_hal_canio_listener_deinit(canio_listener_obj_t *self) {
+    if (self->can) {
+        clear_filters(self);
+        if (self->fifo_idx == 0) {
+            self->can->fifo0_in_use = false;
+        }
+        if (self->fifo_idx == 1) {
+            self->can->fifo1_in_use = false;
+        }
+    }
+    self->fifo_idx = -1;
+    self->fifo = NULL;
+    self->can = NULL;
+    self->hw = NULL;
+}
diff --git a/ports/atmel-samd/common-hal/canio/Listener.h b/ports/atmel-samd/common-hal/canio/Listener.h
new file mode 100644
index 000000000..1b81d82aa
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/Listener.h
@@ -0,0 +1,53 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "common-hal/canio/CAN.h"
+#include "shared-module/canio/Match.h"
+
+typedef struct {
+  __IO CAN_RXF0C_Type            RXFC;       /**< \brief (R/W 32) Rx FIFO n Configuration */
+  __I  CAN_RXF0S_Type            RXFS;       /**< \brief (R/  32) Rx FIFO n Status */
+  __IO CAN_RXF0A_Type            RXFA;       /**< \brief (R/W 32) Rx FIFO n Acknowledge */
+} canio_rxfifo_reg_t;
+
+typedef struct {
+    mp_obj_base_t base;
+    canio_can_obj_t *can;
+    canio_can_rx_fifo_t *fifo;
+    canio_rxfifo_reg_t *hw;
+    uint32_t timeout_ms;
+    uint8_t fifo_idx;
+} canio_listener_obj_t;
+
+void common_hal_canio_listener_construct(canio_listener_obj_t *self, canio_can_obj_t *can, size_t nmatch, canio_match_obj_t **matches, float timeout);
+void common_hal_canio_listener_check_for_deinit(canio_listener_obj_t *self);
+void common_hal_canio_listener_deinit(canio_listener_obj_t *self);
+bool common_hal_canio_listener_readinto(canio_listener_obj_t *self, canio_message_obj_t *message);
+int common_hal_canio_listener_in_waiting(canio_listener_obj_t *self);
+float common_hal_canio_listener_get_timeout(canio_listener_obj_t *self);
+void common_hal_canio_listener_set_timeout(canio_listener_obj_t *self, float timeout);
diff --git a/ports/atmel-samd/common-hal/canio/__init__.c b/ports/atmel-samd/common-hal/canio/__init__.c
new file mode 100644
index 000000000..7932bfc2d
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/__init__.c
@@ -0,0 +1,25 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
diff --git a/ports/atmel-samd/common-hal/canio/__init__.h b/ports/atmel-samd/common-hal/canio/__init__.h
new file mode 100644
index 000000000..32adc5bf9
--- /dev/null
+++ b/ports/atmel-samd/common-hal/canio/__init__.h
@@ -0,0 +1,66 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "hal/utils/include/utils.h"
+#include "component/can.h"
+
+#define COMMON_HAL_CANIO_MAX_MESSAGE_LENGTH (8)
+#define COMMON_HAL_CANIO_RX_FIFO_SIZE (3)
+#define COMMON_HAL_CANIO_RX_FILTER_SIZE (4)
+#define COMMON_HAL_CANIO_TX_FIFO_SIZE (1)
+
+// This appears to be a typo (transposition error) in the ASF4 headers
+// It's called the "Extended ID Filter Entry"
+typedef CanMramXifde CanMramXidfe;
+
+typedef struct canio_listener canio_listener_t;
+typedef struct canio_can canio_can_t;
+
+typedef struct {
+    CAN_TXBE_0_Type txb0;
+    CAN_TXBE_1_Type txb1;
+    COMPILER_ALIGNED(4)
+    uint8_t data[COMMON_HAL_CANIO_MAX_MESSAGE_LENGTH];
+} canio_can_tx_buffer_t;
+
+typedef struct {
+    CAN_RXF0E_0_Type rxf0;
+    CAN_RXF0E_1_Type rxf1;
+    COMPILER_ALIGNED(4)
+    uint8_t data[COMMON_HAL_CANIO_MAX_MESSAGE_LENGTH];
+} canio_can_rx_fifo_t;
+
+typedef uint32_t canio_can_filter_t;
+
+typedef struct {
+    canio_can_tx_buffer_t tx_buffer[COMMON_HAL_CANIO_TX_FIFO_SIZE];
+    canio_can_rx_fifo_t rx0_fifo[COMMON_HAL_CANIO_RX_FIFO_SIZE];
+    canio_can_rx_fifo_t rx1_fifo[COMMON_HAL_CANIO_RX_FIFO_SIZE];
+    CanMramSidfe standard_rx_filter[COMMON_HAL_CANIO_RX_FILTER_SIZE];
+    CanMramXifde extended_rx_filter[COMMON_HAL_CANIO_RX_FILTER_SIZE];
+} canio_can_state_t;
diff --git a/ports/atmel-samd/common-hal/microcontroller/Pin.c b/ports/atmel-samd/common-hal/microcontroller/Pin.c
index ef1d8fffa..bec9dc1e2 100644
--- a/ports/atmel-samd/common-hal/microcontroller/Pin.c
+++ b/ports/atmel-samd/common-hal/microcontroller/Pin.c
@@ -24,6 +24,8 @@
  * THE SOFTWARE.
  */
 
+#include "py/runtime.h"
+
 #include "shared-bindings/microcontroller/Pin.h"
 
 #include "atmel_start_pins.h"
@@ -256,3 +258,19 @@ void common_hal_mcu_pin_claim(const mcu_pin_obj_t* pin) {
 void common_hal_mcu_pin_reset_number(uint8_t pin_no) {
     reset_pin_number(pin_no);
 }
+
+mcu_pin_function_t *mcu_find_pin_function(mcu_pin_function_t *table, const mcu_pin_obj_t *pin, int instance, uint16_t name) {
+    if (!pin) {
+        return NULL;
+    }
+
+    for(; table->obj; table++) {
+        if (instance != -1 && instance != table->instance) {
+            continue;
+        }
+        if (pin == table->obj) {
+            return table;
+        }
+    }
+    mp_raise_ValueError_varg(translate("%q pin invalid"), name);
+}
diff --git a/ports/atmel-samd/common-hal/microcontroller/Pin.h b/ports/atmel-samd/common-hal/microcontroller/Pin.h
index 14887207a..59302713a 100644
--- a/ports/atmel-samd/common-hal/microcontroller/Pin.h
+++ b/ports/atmel-samd/common-hal/microcontroller/Pin.h
@@ -47,4 +47,13 @@ void never_reset_pin_number(uint8_t pin_number);
 void claim_pin(const mcu_pin_obj_t* pin);
 bool pin_number_is_free(uint8_t pin_number);
 
+typedef struct {
+    const mcu_pin_obj_t *obj;
+    uint8_t instance;
+    uint8_t pin;
+    uint16_t function;
+} mcu_pin_function_t;
+
+mcu_pin_function_t *mcu_find_pin_function(mcu_pin_function_t *table, const mcu_pin_obj_t *pin, int instance, uint16_t name);
+
 #endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_MICROCONTROLLER_PIN_H
diff --git a/ports/atmel-samd/common-hal/sdioio/SDCard.c b/ports/atmel-samd/common-hal/sdioio/SDCard.c
index 1f555b647..4d2539aa5 100644
--- a/ports/atmel-samd/common-hal/sdioio/SDCard.c
+++ b/ports/atmel-samd/common-hal/sdioio/SDCard.c
@@ -58,24 +58,6 @@
 
 static Sdhc *sdhc_insts[] = SDHC_INSTS;
 
-STATIC pin_function_t *find_pin_function(pin_function_t *table, const mcu_pin_obj_t *pin, int instance, uint16_t name) {
-    DEBUG_PRINT("\n\n[inst=% 2d] %q: ", instance, name);
-    DEBUG_PRINT_OBJ_NL(pin);
-
-    for(; table->obj; table++) {
-        DEBUG_PRINT("[inst=% 2d] considering table @%p: ");
-        DEBUG_PRINT_OBJ(table->obj);
-        DEBUG_PRINT(" %d %d\n", table->instance, table->pin);
-        if (instance != -1 && instance != table->instance) {
-            continue;
-        }
-        if (pin == table->obj) {
-            return table;
-        }
-    }
-    mp_raise_ValueError_varg(translate("%q pin invalid"), name);
-}
-
 void common_hal_sdioio_sdcard_construct(sdioio_sdcard_obj_t *self,
         const mcu_pin_obj_t * clock, const mcu_pin_obj_t * command,
         uint8_t num_data, mcu_pin_obj_t ** data, uint32_t frequency) {
@@ -98,15 +80,15 @@ CLK PA21 PCC_D? (D32)  BROWN
 
 */
 
-    pin_function_t *functions[6] = {};
-    functions[0] = find_pin_function(sdio_cmd, command, -1, MP_QSTR_command);
+    mcu_pin_function_t *functions[6] = {};
+    functions[0] = mcu_find_pin_function(sdio_cmd, command, -1, MP_QSTR_command);
     int instance = functions[0]->instance;
-    functions[1] = find_pin_function(sdio_ck, clock, instance, MP_QSTR_clock);
-    functions[2] = find_pin_function(sdio_dat0, data[0], instance, MP_QSTR_data0);
+    functions[1] = mcu_find_pin_function(sdio_ck, clock, instance, MP_QSTR_clock);
+    functions[2] = mcu_find_pin_function(sdio_dat0, data[0], instance, MP_QSTR_data0);
     if(num_data == 4) {
-        functions[3] = find_pin_function(sdio_dat1, data[1], instance, MP_QSTR_data1);
-        functions[4] = find_pin_function(sdio_dat2, data[2], instance, MP_QSTR_data2);
-        functions[5] = find_pin_function(sdio_dat3, data[3], instance, MP_QSTR_data3);
+        functions[3] = mcu_find_pin_function(sdio_dat1, data[1], instance, MP_QSTR_data1);
+        functions[4] = mcu_find_pin_function(sdio_dat2, data[2], instance, MP_QSTR_data2);
+        functions[5] = mcu_find_pin_function(sdio_dat3, data[3], instance, MP_QSTR_data3);
     }
 
     // We've verified all pins, now set their special functions
@@ -114,7 +96,7 @@ CLK PA21 PCC_D? (D32)  BROWN
     self->clock_pin = common_hal_mcu_pin_number(functions[1]->obj);
 
     for(int i=0; i<num_data; i++) {
-        pin_function_t *function = functions[2+i];
+        mcu_pin_function_t *function = functions[2+i];
         if (function) {
             self->data_pins[i] = common_hal_mcu_pin_number(function->obj);
         } else {
diff --git a/ports/atmel-samd/tools/mkcandata.py b/ports/atmel-samd/tools/mkcandata.py
new file mode 100755
index 000000000..9668d2208
--- /dev/null
+++ b/ports/atmel-samd/tools/mkcandata.py
@@ -0,0 +1,31 @@
+#!/usr/bin/python3
+
+def defines(name, suffix):
+    print(f'mcu_pin_function_t {name} [] = {{')
+    for instance in (0, 1):
+        for function in 'HI':
+            for port in 'ABCD':
+                for idx in range(32):
+                    pin = f'P{port}{idx:02d}'
+                    pinmux = f'PINMUX_{pin}{function}_CAN{instance}_{suffix}'
+                    print(f'''\
+#if defined({pinmux}) && ! defined(IGNORE_PIN_{pin})
+    {{&pin_{pin}, {instance}, PIN_{pin}, {pinmux} & 0xffff}},
+#endif''')
+    print(f'{{NULL, 0, 0}}')
+    print(f'}};')
+    print()
+
+print('''\
+#include <stdint.h>
+#include "py/obj.h"
+#include "sam.h"
+#include "samd/pins.h"
+#include "mpconfigport.h"
+#include "atmel_start_pins.h"
+#include "hal/include/hal_gpio.h"
+#include "common-hal/microcontroller/Pin.h"
+''')
+
+defines('can_rx', 'RX')
+defines('can_tx', 'TX')
diff --git a/ports/atmel-samd/tools/mksdiodata.py b/ports/atmel-samd/tools/mksdiodata.py
index 0cce3819f..48c4a085f 100755
--- a/ports/atmel-samd/tools/mksdiodata.py
+++ b/ports/atmel-samd/tools/mksdiodata.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python3
 
 def defines(name, function):
-    print(f'pin_function_t {name} [] = {{')
+    print(f'mcu_pin_function_t {name} [] = {{')
     for instance in (0, 1):
         for port in 'ABCD':
             for idx in range(32):
@@ -23,13 +23,8 @@ print('''\
 #include "mpconfigport.h"
 #include "atmel_start_pins.h"
 #include "hal/include/hal_gpio.h"
+#include "common-hal/microcontroller/Pin.h"
 
-typedef struct {
-    const mcu_pin_obj_t *obj;
-    uint8_t instance;
-    uint8_t pin;
-    uint16_t function;
-} pin_function_t;
 ''')
 
 defines('sdio_ck', 'SDCK')
diff --git a/py/circuitpy_defns.mk b/py/circuitpy_defns.mk
index 6e98af868..98fa7a5f2 100644
--- a/py/circuitpy_defns.mk
+++ b/py/circuitpy_defns.mk
@@ -142,6 +142,9 @@ endif
 ifeq ($(CIRCUITPY_CAMERA),1)
 SRC_PATTERNS += camera/%
 endif
+ifeq ($(CIRCUITPY_CANIO),1)
+SRC_PATTERNS += canio/%
+endif
 ifeq ($(CIRCUITPY_COUNTIO),1)
 SRC_PATTERNS += countio/%
 endif
@@ -315,6 +318,9 @@ SRC_COMMON_HAL_ALL = \
 	busio/__init__.c \
 	camera/__init__.c \
 	camera/Camera.c \
+	canio/CAN.c \
+	canio/Listener.c \
+	canio/__init__.c \
 	countio/Counter.c \
 	countio/__init__.c \
 	digitalio/DigitalInOut.c \
@@ -384,6 +390,7 @@ $(filter $(SRC_PATTERNS), \
 	_bleio/Address.c \
 	_bleio/Attribute.c \
 	_bleio/ScanEntry.c \
+	canio/Match.c \
 	_eve/__init__.c \
 	camera/ImageFormat.c \
 	digitalio/Direction.c \
@@ -402,6 +409,8 @@ SRC_SHARED_MODULE_ALL = \
 	_bleio/Attribute.c \
 	_bleio/ScanEntry.c \
 	_bleio/ScanResults.c \
+	canio/Match.c \
+	canio/Message.c \
 	_eve/__init__.c \
 	_pixelbuf/PixelBuf.c \
 	_pixelbuf/__init__.c \
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index 4272de2ec..0583ae1c9 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -336,6 +336,13 @@ extern const struct _mp_obj_module_t camera_module;
 #define CAMERA_MODULE
 #endif
 
+#if CIRCUITPY_CANIO
+extern const struct _mp_obj_module_t canio_module;
+#define CANIO_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR_canio), (mp_obj_t)&canio_module },
+#else
+#define CANIO_MODULE
+#endif
+
 #if CIRCUITPY_COUNTIO
 extern const struct _mp_obj_module_t countio_module;
 #define COUNTIO_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_countio), (mp_obj_t)&countio_module },
@@ -766,6 +773,7 @@ extern const struct _mp_obj_module_t wifi_module;
     BOARD_MODULE \
     BUSIO_MODULE \
     CAMERA_MODULE \
+    CANIO_MODULE \
     COUNTIO_MODULE \
     DIGITALIO_MODULE \
     DISPLAYIO_MODULE \
diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index 54bdefc6d..9b9bd83b4 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -93,6 +93,9 @@ CFLAGS += -DCIRCUITPY_BUSIO=$(CIRCUITPY_BUSIO)
 CIRCUITPY_CAMERA ?= 0
 CFLAGS += -DCIRCUITPY_CAMERA=$(CIRCUITPY_CAMERA)
 
+CIRCUITPY_CANIO ?= 0
+CFLAGS += -DCIRCUITPY_CANIO=$(CIRCUITPY_CANIO)
+
 CIRCUITPY_DIGITALIO ?= 1
 CFLAGS += -DCIRCUITPY_DIGITALIO=$(CIRCUITPY_DIGITALIO)
 
diff --git a/py/enum.c b/py/enum.c
new file mode 100644
index 000000000..02a85a168
--- /dev/null
+++ b/py/enum.c
@@ -0,0 +1,52 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+#include "py/runtime.h"
+
+mp_obj_t cp_enum_find(const mp_obj_type_t *type, int value) {
+    const mp_obj_dict_t *dict = type->locals_dict;
+    for (size_t i=0; i<dict->map.used; i++) {
+        const cp_enum_obj_t *v = dict->map.table[i].value;
+        if (v->value == value) {
+            return (mp_obj_t)v;
+        }
+    }
+    return mp_const_none;
+}
+
+int cp_enum_value(const mp_obj_type_t *type, mp_obj_t *obj) {
+    if (!MP_OBJ_IS_TYPE(obj, type)) {
+        mp_raise_TypeError_varg(translate("Expected a %q"), type->name);
+    }
+    return ((cp_enum_obj_t*)MP_OBJ_TO_PTR(obj))->value;
+}
+
+void cp_enum_obj_print_helper(uint16_t module, const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    (void) kind;
+    cp_enum_obj_t *self = self_in;
+    mp_printf(print, "%q.%q.%q", module, self->base.type->name, self->name);
+}
diff --git a/py/enum.h b/py/enum.h
new file mode 100644
index 000000000..1c38ae5ae
--- /dev/null
+++ b/py/enum.h
@@ -0,0 +1,65 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    int16_t value;
+    int16_t name;
+} cp_enum_obj_t;
+
+#define MAKE_ENUM_VALUE(type, prefix, name, value) \
+    STATIC const cp_enum_obj_t prefix ## _ ## name ## _obj = { \
+        { &type }, value, MP_QSTR_ ## name, \
+    }
+
+#define MAKE_ENUM_MAP(name) \
+    STATIC const mp_rom_map_elem_t name ## _locals_table[] =
+
+#define MAKE_ENUM_MAP_ENTRY(prefix, name) \
+    { MP_ROM_QSTR(MP_QSTR_ ## name), MP_ROM_PTR(&prefix ## _ ## name ## _obj) }
+
+#define MAKE_PRINTER(module, typename) \
+    STATIC void typename ## _ ## print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) { \
+        cp_enum_obj_print_helper(MP_QSTR_ ## module, print, self_in, kind); \
+    }
+
+#define MAKE_ENUM_TYPE(module, type, typename) \
+    const mp_obj_type_t typename ## _type = { \
+        { &mp_type_type }, \
+        .name = MP_QSTR_ ## type, \
+        .print = typename ## _print, \
+        .locals_dict = (mp_obj_t)&typename ## _locals_dict, \
+    }
+
+
+
+mp_obj_t cp_enum_find(const mp_obj_type_t *type, int value);
+int cp_enum_value(const mp_obj_type_t *type, mp_obj_t *obj);
+void cp_enum_obj_print_helper(uint16_t module, const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind);
diff --git a/py/py.mk b/py/py.mk
index 49fb0acaf..acf5d127b 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -181,6 +181,7 @@ PY_CORE_O_BASENAME = $(addprefix py/,\
 	argcheck.o \
 	warning.o \
 	map.o \
+	enum.o \
 	obj.o \
 	objarray.o \
 	objattrtuple.o \
diff --git a/shared-bindings/canio/CAN.c b/shared-bindings/canio/CAN.c
new file mode 100644
index 000000000..ff27bb204
--- /dev/null
+++ b/shared-bindings/canio/CAN.c
@@ -0,0 +1,422 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+#include "common-hal/canio/CAN.h"
+#include "common-hal/canio/Listener.h"
+#include "shared-bindings/canio/__init__.h"
+#include "shared-bindings/canio/CAN.h"
+#include "shared-bindings/canio/Listener.h"
+#include "shared-bindings/canio/Match.h"
+#include "shared-bindings/canio/Message.h"
+#include "shared-bindings/microcontroller/Pin.h"
+
+#include "py/objproperty.h"
+#include "py/runtime.h"
+
+//|
+//| class CAN:
+//|     """CAN bus protocol"""
+//|
+//|     def __init__(self,
+//|             tx: microcontroller.Pin,
+//|             rx: microcontroller.Pin,
+//|             *,
+//|             baudrate: int = 250000,
+//|             loopback: bool = False,
+//|             silent: bool = False,
+//|             auto_restart: bool = False,
+//|         ):
+//|         """A common shared-bus protocol.  The rx and tx pins are generally
+//|         connected to a transceiver which controls the H and L pins on a
+//|         shared bus.
+//|
+//|         :param ~microcontroller.Pin rx: the pin to receive with
+//|         :param ~microcontroller.Pin tx: the pin to transmit with
+//|         :param int baudrate: The bit rate of the bus in Hz.  All devices on the bus must agree on this value.
+//|         :param bool loopback: When True  the ``rx`` pin's value is ignored, and the device receives the packets it sends.
+//|         :param bool silent: When True the ``tx`` pin is always driven to the high logic level.  This mode can be used to "sniff" a CAN bus without interfering.
+//|         :param bool auto_restart: If True, will restart communications after entering bus-off state
+//|         """
+//|         ...
+//|
+STATIC mp_obj_t canio_can_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_tx, ARG_rx, ARG_baudrate, ARG_loopback, ARG_silent, ARG_auto_restart, NUM_ARGS };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_tx, MP_ARG_OBJ | MP_ARG_REQUIRED },
+        { MP_QSTR_rx, MP_ARG_OBJ | MP_ARG_REQUIRED },
+        { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 250000} },
+        { MP_QSTR_loopback, MP_ARG_BOOL, {.u_bool = false} },
+        { MP_QSTR_silent, MP_ARG_BOOL, {.u_bool = false} },
+        { MP_QSTR_auto_restart, MP_ARG_BOOL, {.u_bool = false} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    MP_STATIC_ASSERT( MP_ARRAY_SIZE(allowed_args) == NUM_ARGS );
+
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mcu_pin_obj_t *rx_pin = validate_obj_is_free_pin_or_none(args[ARG_rx].u_obj);
+    mcu_pin_obj_t *tx_pin = validate_obj_is_free_pin_or_none(args[ARG_tx].u_obj);
+    if (!rx_pin && !tx_pin) {
+        mp_raise_ValueError(translate("tx and rx cannot both be None"));
+    }
+
+    canio_can_obj_t *self = m_new_obj(canio_can_obj_t);
+    self->base.type = &canio_can_type;
+    common_hal_canio_can_construct(self, tx_pin, rx_pin, args[ARG_baudrate].u_int, args[ARG_loopback].u_bool, args[ARG_silent].u_bool);
+
+    common_hal_canio_can_auto_restart_set(self, args[ARG_auto_restart].u_bool);
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+
+//|     auto_restart: bool
+//|     """If True, will restart communications after entering bus-off state"""
+//|
+STATIC mp_obj_t canio_can_auto_restart_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return mp_obj_new_bool(common_hal_canio_can_auto_restart_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_auto_restart_get_obj, canio_can_auto_restart_get);
+
+STATIC mp_obj_t canio_can_auto_restart_set(mp_obj_t self_in, mp_obj_t flag_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    common_hal_canio_can_auto_restart_set(self, mp_obj_is_true(flag_in));
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_can_auto_restart_set_obj, canio_can_auto_restart_set);
+
+STATIC const mp_obj_property_t canio_can_auto_restart_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_auto_restart_get_obj,
+              (mp_obj_t)&canio_can_auto_restart_set_obj,
+              (mp_obj_t)mp_const_none},
+};
+
+
+//|     baudrate: int
+//|     """The baud rate (read-only)"""
+//|
+STATIC mp_obj_t canio_can_baudrate_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_baudrate_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_baudrate_get_obj, canio_can_baudrate_get);
+
+STATIC const mp_obj_property_t canio_can_baudrate_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_baudrate_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     transmit_error_count: int
+//|     """The number of transmit errors (read-only).  Increased for a detected transmission error, decreased for successful transmission.  Limited to the range from 0 to 255 inclusive.  Also called TEC."""
+//|
+STATIC mp_obj_t canio_can_transmit_error_count_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_transmit_error_count_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_transmit_error_count_get_obj, canio_can_transmit_error_count_get);
+
+STATIC const mp_obj_property_t canio_can_transmit_error_count_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_transmit_error_count_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     receive_error_count: int
+//|     """The number of receive errors (read-only).  Increased for a detected reception error, decreased for successful reception.  Limited to the range from 0 to 255 inclusive.  Also called REC."""
+//|
+STATIC mp_obj_t canio_can_receive_error_count_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_receive_error_count_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_receive_error_count_get_obj, canio_can_receive_error_count_get);
+
+STATIC const mp_obj_property_t canio_can_receive_error_count_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_receive_error_count_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     error_warning_state_count: int
+//|     """The number of times the controller enterted the Error Warning state (read-only).  This number wraps around to 0 after an implementation-defined number of errors."""
+//|
+STATIC mp_obj_t canio_can_error_warning_state_count_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_error_warning_state_count_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_error_warning_state_count_get_obj, canio_can_error_warning_state_count_get);
+
+STATIC const mp_obj_property_t canio_can_error_warning_state_count_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_error_warning_state_count_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     error_passive_state_count: int
+//|     """The number of times the controller enterted the Error Passive state (read-only).  This number wraps around to 0 after an implementation-defined number of errors."""
+//|
+STATIC mp_obj_t canio_can_error_passive_state_count_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_error_passive_state_count_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_error_passive_state_count_get_obj, canio_can_error_passive_state_count_get);
+
+STATIC const mp_obj_property_t canio_can_error_passive_state_count_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_error_passive_state_count_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     bus_off_state_count: int
+//|     """The number of times the controller enterted the Bus Off state (read-only).  This number wraps around to 0 after an implementation-defined number of errors."""
+//|
+STATIC mp_obj_t canio_can_bus_off_state_count_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_can_bus_off_state_count_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_bus_off_state_count_get_obj, canio_can_bus_off_state_count_get);
+
+STATIC const mp_obj_property_t canio_can_bus_off_state_count_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_bus_off_state_count_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+//|     state: State
+//|     """The current state of the bus."""
+STATIC mp_obj_t canio_can_state_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return cp_enum_find(&canio_bus_state_type, common_hal_canio_can_state_get(self));
+}
+
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_state_get_obj, canio_can_state_get);
+
+STATIC const mp_obj_property_t canio_can_state_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_state_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+
+//|     def restart(self) -> None:
+//|         """If the device is in the bus off state, restart it."""
+//|         ...
+//|
+STATIC mp_obj_t canio_can_restart(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    common_hal_canio_can_restart(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_can_restart_obj, canio_can_restart);
+
+//|     def listen(self, match: Optional[Sequence[Match]]=None, *, timeout: float=10) -> Listener:
+//|         """Start receiving messages that match any one of the filters.
+//|
+//|         Creating a listener is an expensive operation and can interfere with reception of messages by other listeners.
+//|
+//|         There is an implementation-defined maximum number of listeners and limit to the complexity of the filters.
+//|
+//|         If the hardware cannot support all the requested matches, a ValueError is raised.  Note that generally there are some number of hardware filters shared among all fifos.
+//|
+//|         A message can be received by at most one Listener.  If more than one listener matches a message, it is undefined which one actually receives it.
+//|
+//|         An empty filter list causes all messages to be accepted.
+//|
+//|         Timeout dictates how long readinto, read and next() will block."""
+//|         ...
+//|
+STATIC mp_obj_t canio_can_listen(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
+    common_hal_canio_can_check_for_deinit(self);
+
+    enum { ARG_match, ARG_timeout, NUM_ARGS };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_match, MP_ARG_OBJ, {.u_obj = 0} },
+        { MP_QSTR_timeout, MP_ARG_OBJ, {.u_obj = 0} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    MP_STATIC_ASSERT( MP_ARRAY_SIZE(allowed_args) == NUM_ARGS );
+
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    size_t nmatch = 0;
+    mp_obj_t *match_objects = NULL;
+
+    if (args[ARG_match].u_obj) {
+        mp_obj_get_array(args[ARG_match].u_obj, &nmatch, &match_objects);
+    }
+
+    canio_match_obj_t *matches[nmatch];
+    for (size_t i=0; i<nmatch; i++) {
+        mp_obj_type_t *type = mp_obj_get_type(match_objects[i]);
+        if (type != &canio_match_type) {
+            mp_raise_TypeError_varg(translate("expected '%q' but got '%q'"), MP_QSTR_Match, type->name);
+        }
+        matches[i] = MP_OBJ_TO_PTR(match_objects[i]);
+    }
+
+    float timeout = args[ARG_timeout].u_obj ? mp_obj_get_float(args[ARG_timeout].u_obj) : 10.0f;
+    canio_listener_obj_t *listener = m_new_obj(canio_listener_obj_t);
+    listener->base.type = &canio_listener_type;
+    common_hal_canio_listener_construct(listener, self, nmatch, matches, timeout);
+    return listener;
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(canio_can_listen_obj, 1, canio_can_listen);
+
+//|     loopback: bool
+//|     """True if the device was created in loopback mode, False otherwise"""
+//|
+STATIC mp_obj_t canio_can_loopback_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return mp_obj_new_bool(common_hal_canio_can_loopback_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_loopback_get_obj, canio_can_loopback_get);
+
+STATIC const mp_obj_property_t canio_can_loopback_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_loopback_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+
+//|     def send(message: Message) -> None:
+//|         """Send a message on the bus with the given data and id.
+//|         If the message could not be sent due to a full fifo or a bus error condition, RuntimeError is raised.
+//|         """
+//|         ...
+//|
+STATIC mp_obj_t canio_can_send(mp_obj_t self_in, mp_obj_t message_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    mp_obj_type_t *message_type = mp_obj_get_type(message_in);
+    if (message_type != &canio_message_type) {
+        mp_raise_TypeError_varg(translate("expected '%q' but got '%q'"), MP_QSTR_Message, message_type->name);
+    }
+
+    canio_message_obj_t *message = message_in;
+    common_hal_canio_can_send(self, message);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_can_send_obj, canio_can_send);
+
+//|     silent: bool
+//|     """True if the device was created in silent mode, False otherwise"""
+//|
+STATIC mp_obj_t canio_can_silent_get(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return mp_obj_new_bool(common_hal_canio_can_silent_get(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_can_silent_get_obj, canio_can_silent_get);
+
+STATIC const mp_obj_property_t canio_can_silent_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_can_silent_get_obj,
+              (mp_obj_t)mp_const_none,
+              (mp_obj_t)mp_const_none},
+};
+
+
+//|     def deinit(self) -> None:
+//|         """Deinitialize this object, freeing its hardware resources"""
+//|         ...
+//|
+STATIC mp_obj_t canio_can_deinit(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_deinit(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_can_deinit_obj, canio_can_deinit);
+
+//|     def __enter__(self) -> CAN:
+//|         """Returns self, to allow the object to be used in a `with` statement for resource control"""
+//|         ...
+//|
+STATIC mp_obj_t canio_can_enter(mp_obj_t self_in) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_can_check_for_deinit(self);
+    return self_in;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_can_enter_obj, canio_can_enter);
+
+//|     def __exit__(self, unused1, unused2, unused3) -> None:
+//|         """Calls deinit()"""
+//|         ...
+STATIC mp_obj_t canio_can_exit(size_t num_args, const mp_obj_t args[]) {
+    canio_can_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    common_hal_canio_can_deinit(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(canio_can_exit_obj, 4, 4, canio_can_exit);
+
+STATIC const mp_rom_map_elem_t canio_can_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&canio_can_enter_obj) },
+    { MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&canio_can_exit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_auto_restart), MP_ROM_PTR(&canio_can_auto_restart_obj) },
+    { MP_ROM_QSTR(MP_QSTR_baudrate), MP_ROM_PTR(&canio_can_baudrate_obj) },
+    { MP_ROM_QSTR(MP_QSTR_bus_off_state_count), MP_ROM_PTR(&canio_can_bus_off_state_count_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&canio_can_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_error_passive_state_count), MP_ROM_PTR(&canio_can_error_passive_state_count_obj) },
+    { MP_ROM_QSTR(MP_QSTR_error_warning_state_count), MP_ROM_PTR(&canio_can_error_warning_state_count_obj) },
+    { MP_ROM_QSTR(MP_QSTR_listen), MP_ROM_PTR(&canio_can_listen_obj) },
+    { MP_ROM_QSTR(MP_QSTR_loopback), MP_ROM_PTR(&canio_can_loopback_obj) },
+    { MP_ROM_QSTR(MP_QSTR_receive_error_count), MP_ROM_PTR(&canio_can_receive_error_count_obj) },
+    { MP_ROM_QSTR(MP_QSTR_restart), MP_ROM_PTR(&canio_can_restart_obj) },
+    { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&canio_can_send_obj) },
+    { MP_ROM_QSTR(MP_QSTR_silent), MP_ROM_PTR(&canio_can_silent_obj) },
+    { MP_ROM_QSTR(MP_QSTR_state), MP_ROM_PTR(&canio_can_state_obj) },
+    { MP_ROM_QSTR(MP_QSTR_transmit_error_count), MP_ROM_PTR(&canio_can_transmit_error_count_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(canio_can_locals_dict, canio_can_locals_dict_table);
+
+const mp_obj_type_t canio_can_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_CAN,
+    .make_new = canio_can_make_new,
+    .locals_dict = (mp_obj_t)&canio_can_locals_dict,
+};
diff --git a/shared-bindings/canio/CAN.h b/shared-bindings/canio/CAN.h
new file mode 100644
index 000000000..66c972c28
--- /dev/null
+++ b/shared-bindings/canio/CAN.h
@@ -0,0 +1,54 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/canio/Message.h"
+
+extern const mp_obj_type_t canio_can_type;
+
+typedef struct canio_can_obj canio_can_obj_t;
+
+void common_hal_canio_can_construct(canio_can_obj_t *self, mcu_pin_obj_t *tx, mcu_pin_obj_t *rx, int baudrate, bool loopback, bool silent);
+bool common_hal_canio_can_auto_restart_get(canio_can_obj_t *self);
+bool common_hal_canio_can_deinited(canio_can_obj_t *self);
+int common_hal_canio_can_baudrate_get(canio_can_obj_t *self);
+int common_hal_canio_can_bus_off_state_count_get(canio_can_obj_t *self);
+int common_hal_canio_can_error_passive_state_count_get(canio_can_obj_t *self);
+int common_hal_canio_can_error_warning_state_count_get(canio_can_obj_t *self);
+bool common_hal_canio_can_loopback_get(canio_can_obj_t *self);
+int common_hal_canio_can_receive_error_count_get(canio_can_obj_t *self);
+canio_bus_state_t common_hal_canio_can_state_get(canio_can_obj_t *self);
+bool common_hal_canio_can_silent_get(canio_can_obj_t *self);
+int common_hal_canio_can_transmit_error_count_get(canio_can_obj_t *self);
+void common_hal_canio_can_auto_restart_set(canio_can_obj_t *self, bool auto_restart);
+void common_hal_canio_can_check_for_deinit(canio_can_obj_t *self);
+void common_hal_canio_can_deinit(canio_can_obj_t *self);
+void common_hal_canio_can_restart(canio_can_obj_t *self);
+void common_hal_canio_can_send(canio_can_obj_t *self, canio_message_obj_t *message);
+void common_hal_canio_reset(void);
diff --git a/shared-bindings/canio/Listener.c b/shared-bindings/canio/Listener.c
new file mode 100644
index 000000000..1f4176f0c
--- /dev/null
+++ b/shared-bindings/canio/Listener.c
@@ -0,0 +1,185 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/canio/Listener.h"
+#include "shared-bindings/canio/Message.h"
+#include "common-hal/canio/Listener.h"
+
+#include "py/runtime.h"
+#include "py/objproperty.h"
+
+//| class Listener:
+//|     """Listens for CAN message
+//|
+//|     canio.Listener is not constructed directly, but instead by calling the
+//|     Listen method of a canio.CAN object."""
+//|
+
+//|     def read(self) -> Optional[Message]:
+//|         """Reads a message, after waiting up to self.timeout seconds
+//|
+//|         If no message is received in time, None is returned.  Otherwise,
+//|         a Message is returned."""
+//|         ...
+//|
+STATIC mp_obj_t canio_listener_read(mp_obj_t self_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_check_for_deinit(self);
+
+    canio_message_obj_t *message = m_new_obj(canio_message_obj_t);
+    message->base.type = &canio_message_type;
+
+    if (common_hal_canio_listener_readinto(self, message)) {
+        return message;
+    } else {
+        m_free(message); // message did not escape into vm
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_listener_read_obj, canio_listener_read);
+
+//|     def readinto(self, message: Message) -> bool:
+//|         """Returns True (and modifies message) if a message was received
+//|         before ``timeout`` seconds elapsed, False otherwise."""
+//|         ...
+//|
+STATIC mp_obj_t canio_listener_readinto(mp_obj_t self_in, mp_obj_t message) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_type_t *type = mp_obj_get_type(message);
+    if (type != &canio_message_type) {
+        mp_raise_TypeError_varg(translate("expected '%q' but got '%q'"), MP_QSTR_Message, type->name);
+    }
+    common_hal_canio_listener_check_for_deinit(self);
+    return mp_obj_new_bool(common_hal_canio_listener_readinto(self, message));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(canio_listener_readinto_obj, canio_listener_readinto);
+
+//|     def in_waiting(self) -> int:
+//|         """Returns the number of messages waiting"""
+//|         ...
+//|
+STATIC mp_obj_t canio_listener_in_waiting(mp_obj_t self_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_check_for_deinit(self);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_listener_in_waiting(self));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_listener_in_waiting_obj, canio_listener_in_waiting);
+
+//|     def __iter__(self):
+//|         """Returns self, unless the object is deinitialized"""
+//|         ...
+//|
+//|     def __next__(self):
+//|         """Reads a message, after waiting up to self.timeout seconds
+//|
+//|         If no message is received in time, raises StopIteration.  Otherwise,
+//|         a Message is returned."""
+//|         ...
+//|
+STATIC mp_obj_t canio_iternext(mp_obj_t self_in) {
+    mp_obj_t result = canio_listener_read(self_in);
+    if (result == mp_const_none) {
+        return MP_OBJ_STOP_ITERATION;
+    }
+    return result;
+}
+
+//|     def deinit(self) -> None:
+//|         """Deinitialize this object, freeing its hardware resources"""
+//|         ...
+//|
+STATIC mp_obj_t canio_listener_deinit(mp_obj_t self_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_deinit(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_listener_deinit_obj, canio_listener_deinit);
+
+//|     def __enter__(self) -> CAN:
+//|         """Returns self, to allow the object to be used in a `with` statement for resource control"""
+//|         ...
+//|
+STATIC mp_obj_t canio_listener_enter(mp_obj_t self_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_check_for_deinit(self);
+    return self_in;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_listener_enter_obj, canio_listener_enter);
+
+//|     def __exit__(self, unused1, unused2, unused3) -> None:
+//|         """Calls deinit()"""
+//|         ...
+STATIC mp_obj_t canio_listener_exit(size_t num_args, const mp_obj_t args[]) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    common_hal_canio_listener_deinit(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(canio_listener_exit_obj, 4, 4, canio_listener_exit);
+
+
+//|     timeout : float
+STATIC mp_obj_t canio_listener_timeout_get(mp_obj_t self_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_check_for_deinit(self);
+    return mp_obj_new_float(common_hal_canio_listener_get_timeout(self));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(canio_listener_timeout_get_obj, canio_listener_timeout_get);
+
+STATIC mp_obj_t canio_listener_timeout_set(mp_obj_t self_in, mp_obj_t timeout_in) {
+    canio_listener_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_canio_listener_check_for_deinit(self);
+    common_hal_canio_listener_set_timeout(self, mp_obj_get_float(timeout_in));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(canio_listener_timeout_set_obj, canio_listener_timeout_set);
+
+STATIC const mp_obj_property_t canio_listener_timeout_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_listener_timeout_get_obj,
+              (mp_obj_t)&canio_listener_timeout_set_obj,
+              (mp_obj_t)mp_const_none},
+};
+
+
+
+STATIC const mp_rom_map_elem_t canio_listener_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&canio_listener_enter_obj) },
+    { MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&canio_listener_exit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&canio_listener_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_in_waiting), MP_ROM_PTR(&canio_listener_in_waiting_obj) },
+    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&canio_listener_read_obj) },
+    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&canio_listener_readinto_obj) },
+    { MP_ROM_QSTR(MP_QSTR_timeout), MP_ROM_PTR(&canio_listener_timeout_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(canio_listener_locals_dict, canio_listener_locals_dict_table);
+
+const mp_obj_type_t canio_listener_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Listener,
+    .getiter = mp_identity_getiter,
+    .iternext = canio_iternext,
+    .locals_dict = (mp_obj_dict_t*)&canio_listener_locals_dict,
+};
diff --git a/shared-bindings/canio/Listener.h b/shared-bindings/canio/Listener.h
new file mode 100644
index 000000000..eaa3490df
--- /dev/null
+++ b/shared-bindings/canio/Listener.h
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+
+extern const mp_obj_type_t canio_listener_type;
diff --git a/shared-bindings/canio/Match.c b/shared-bindings/canio/Match.c
new file mode 100644
index 000000000..ff5d028fa
--- /dev/null
+++ b/shared-bindings/canio/Match.c
@@ -0,0 +1,139 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/canio/Match.h"
+
+#include "py/objproperty.h"
+#include "py/runtime.h"
+
+//| class Match:
+//|     """Describe CAN bus messages to match"""
+//|
+//|
+//|     def __init__(self, address: int, *, mask: int = 0, extended: bool = False):
+//|         """Construct a Match with the given properties.
+//|
+//|         If mask is nonzero, then the filter is for any sender which matches all
+//|         the nonzero bits in mask. Otherwise, it matches exactly the given address.
+//|         If extended is true then only extended addresses are matched, otherwise
+//|         only standard addresses are matched."""
+//|
+
+STATIC mp_obj_t canio_match_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_address, ARG_mask, ARG_extended, NUM_ARGS };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_address, MP_ARG_INT | MP_ARG_REQUIRED },
+        { MP_QSTR_mask, MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_extended, MP_ARG_BOOL, {.u_bool = false} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    MP_STATIC_ASSERT( MP_ARRAY_SIZE(allowed_args) == NUM_ARGS );
+
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    int address_bits = args[ARG_extended].u_bool ? 0x1fffffff : 0x7ff;
+    int address = args[ARG_address].u_int;
+    int mask = args[ARG_mask].u_int;
+
+    if (address & ~address_bits) {
+        mp_raise_ValueError_varg(translate("%q out of range"), MP_QSTR_address);
+    }
+
+    if (mask & ~address_bits) {
+        mp_raise_ValueError_varg(translate("%q out of range"), MP_QSTR_mask);
+    }
+
+    canio_match_obj_t *self = m_new_obj(canio_match_obj_t);
+    self->base.type = &canio_match_type;
+    common_hal_canio_match_construct(self, args[ARG_address].u_int, args[ARG_mask].u_int, args[ARG_extended].u_bool);
+    return self;
+}
+
+//|     address: int
+//|     """The address to match"""
+//|
+
+STATIC mp_obj_t canio_match_address_get(mp_obj_t self_in) {
+    canio_match_obj_t *self = self_in;
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_match_get_address(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_match_address_get_obj, canio_match_address_get);
+
+const mp_obj_property_t canio_match_address_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_match_address_get_obj,
+              (mp_obj_t)&mp_const_none_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+//|
+//|     mask: int
+//|     """The optional mask of addresses to match"""
+//|
+
+STATIC mp_obj_t canio_match_mask_get(mp_obj_t self_in) {
+    canio_match_obj_t *self = self_in;
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_match_get_mask(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_match_mask_get_obj, canio_match_mask_get);
+
+const mp_obj_property_t canio_match_mask_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_match_mask_get_obj,
+              (mp_obj_t)&mp_const_none_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+//|     extended: bool
+//|     """True to match extended addresses, False to match standard addresses"""
+//|
+
+STATIC mp_obj_t canio_match_extended_get(mp_obj_t self_in) {
+    canio_match_obj_t *self = self_in;
+    return mp_obj_new_bool(common_hal_canio_match_get_extended(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_match_extended_get_obj, canio_match_extended_get);
+
+const mp_obj_property_t canio_match_extended_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_match_extended_get_obj,
+              (mp_obj_t)&mp_const_none_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+STATIC const mp_rom_map_elem_t canio_match_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_address), MP_ROM_PTR(&canio_match_address_obj) },
+    { MP_ROM_QSTR(MP_QSTR_mask), MP_ROM_PTR(&canio_match_mask_obj) },
+    { MP_ROM_QSTR(MP_QSTR_extended), MP_ROM_PTR(&canio_match_extended_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(canio_match_locals_dict, canio_match_locals_dict_table);
+
+const mp_obj_type_t canio_match_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Match,
+    .make_new = canio_match_make_new,
+    .locals_dict = (mp_obj_dict_t*)&canio_match_locals_dict,
+};
diff --git a/shared-bindings/canio/Match.h b/shared-bindings/canio/Match.h
new file mode 100644
index 000000000..88996d730
--- /dev/null
+++ b/shared-bindings/canio/Match.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-module/canio/Match.h"
+
+extern const mp_obj_type_t canio_match_type;
+
+void common_hal_canio_match_construct(canio_match_obj_t *self, int address, int mask, bool extended);
+int common_hal_canio_match_get_address(const canio_match_obj_t *self);
+int common_hal_canio_match_get_mask(const canio_match_obj_t *self);
+bool common_hal_canio_match_get_extended(const canio_match_obj_t *self);
diff --git a/shared-bindings/canio/Message.c b/shared-bindings/canio/Message.c
new file mode 100644
index 000000000..23645d2e5
--- /dev/null
+++ b/shared-bindings/canio/Message.c
@@ -0,0 +1,212 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/canio/Message.h"
+
+#include "py/obj.h"
+#include "py/objproperty.h"
+#include "py/runtime.h"
+
+//| class Message:
+//|     def __init__(self, id: int=0, data: Optional[bytes] = None, *, size: Optional[int] = None, rtr: bool = False, extended: bool = False):
+//|         """Construct a Message to use with a CAN bus.  Provide arguments to create a message to send.  Otherwise, use Listener.readinto() to read a message.
+//|
+//|         :param int id: The numeric ID of the message
+//|         :param bytes data: The content of the message
+//|         :param int size: The amount of data requested, for an rtr
+//|         :param bool rtr: True if the message represents an rtr (Remote Transmission Request)
+//|         :param bool extended: True if the message has an extended identifier, False if it has a standard identifier
+//|
+//|         In CAN, messages can have a size from 0 to 8 bytes.
+//|
+//|         For a non-rtr message, specify ``data``.  For an rtr-message, specify either ``data`` (a dummy buffer of the requested size) or ``size``.
+//|         """
+//|         ...
+//|
+STATIC mp_obj_t canio_message_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_id, ARG_data, ARG_size, ARG_rtr, ARG_extended, NUM_ARGS };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_id, MP_ARG_INT, {.u_obj = 0} },
+        { MP_QSTR_data, MP_ARG_OBJ, {.u_obj = 0} },
+        { MP_QSTR_size, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_rtr, MP_ARG_BOOL, {.u_bool = false} },
+        { MP_QSTR_extended, MP_ARG_BOOL, {.u_bool = false} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    MP_STATIC_ASSERT( MP_ARRAY_SIZE(allowed_args) == NUM_ARGS );
+
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    bool rtr = args[ARG_rtr].u_bool;
+    bool extended = args[ARG_extended].u_bool;
+    size_t size = (size_t)args[ARG_size].u_int;
+    bool specified_size = (size != (size_t)-1);
+    bool specified_data = (args[ARG_data].u_obj != NULL);
+
+    if (specified_size && specified_data) {
+        mp_raise_TypeError(translate("specify size or data, but not both"));
+    }
+
+    mp_buffer_info_t data;
+    if (specified_data) {
+        mp_get_buffer_raise(args[ARG_data].u_obj, &data, MP_BUFFER_READ);
+    } else if (specified_size) {
+        data.buf = 0;
+        data.len = size;
+    } else {
+        data.buf = 0;
+        data.len = 0;
+    }
+
+    if (data.len > 8) {
+        mp_raise_ValueError(translate("Messages limited to 8 bytes"));
+    }
+
+    canio_message_obj_t *self = m_new_obj(canio_message_obj_t);
+    self->base.type = &canio_message_type;
+    common_hal_canio_message_construct(self, args[ARG_id].u_int, data.buf, data.len, rtr, extended);
+    return self;
+}
+
+//|     id: int
+//|     """The numeric ID of the message"""
+//|
+STATIC mp_obj_t canio_message_id_get(const mp_obj_t self_in) {
+    canio_message_obj_t *self = self_in;
+    return MP_OBJ_NEW_SMALL_INT(common_hal_canio_message_get_id(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_message_id_get_obj, canio_message_id_get);
+
+STATIC mp_obj_t canio_message_id_set(const mp_obj_t self_in, const mp_obj_t id) {
+    canio_message_obj_t *self = self_in;
+    common_hal_canio_message_set_id(self, mp_obj_get_int(id));
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_message_id_set_obj, canio_message_id_set);
+
+STATIC const mp_obj_property_t canio_message_id_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_message_id_get_obj,
+              (mp_obj_t)&canio_message_id_set_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+//|     data: bytes
+//|     """The content of the message, or dummy content in the case of an rtr.
+//|
+//|     Assigning to data also sets the length and clears the rtr flag."""
+//|
+STATIC mp_obj_t canio_message_data_get(const mp_obj_t self_in) {
+    canio_message_obj_t *self = self_in;
+    return mp_obj_new_bytes((const byte*)common_hal_canio_message_get_data(self), common_hal_canio_message_get_size(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_message_data_get_obj, canio_message_data_get);
+
+STATIC mp_obj_t canio_message_data_set(const mp_obj_t self_in, const mp_obj_t data_in) {
+    canio_message_obj_t *self = self_in;
+    mp_buffer_info_t data;
+    mp_get_buffer_raise(data_in, &data, MP_BUFFER_READ);
+    if (data.len > 8) {
+        mp_raise_ValueError(translate("Messages limited to 8 bytes"));
+    }
+    common_hal_canio_message_set_data(self, data.buf, data.len);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_message_data_set_obj, canio_message_data_set);
+
+
+STATIC const mp_obj_property_t canio_message_data_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_message_data_get_obj,
+              (mp_obj_t)&canio_message_data_set_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+
+//|     extended: bool
+//|     """True if the message represents a remote transmission request (RTR)"""
+//|
+STATIC mp_obj_t canio_message_extended_get(const mp_obj_t self_in) {
+    canio_message_obj_t *self = self_in;
+    return mp_obj_new_bool(common_hal_canio_message_get_extended(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_message_extended_get_obj, canio_message_extended_get);
+
+STATIC mp_obj_t canio_message_extended_set(const mp_obj_t self_in, const mp_obj_t extended) {
+    canio_message_obj_t *self = self_in;
+    common_hal_canio_message_set_extended(self, mp_obj_is_true(extended));
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_message_extended_set_obj, canio_message_extended_set);
+
+
+STATIC const mp_obj_property_t canio_message_extended_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_message_extended_get_obj,
+              (mp_obj_t)&canio_message_extended_set_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+
+//|     rtr: bool
+//|     """True if the message represents a remote transmission request (RTR).  Setting rtr to true zeros out data"""
+//|
+STATIC mp_obj_t canio_message_rtr_get(const mp_obj_t self_in) {
+    canio_message_obj_t *self = self_in;
+    return mp_obj_new_bool(common_hal_canio_message_get_rtr(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(canio_message_rtr_get_obj, canio_message_rtr_get);
+
+STATIC mp_obj_t canio_message_rtr_set(const mp_obj_t self_in, const mp_obj_t rtr) {
+    canio_message_obj_t *self = self_in;
+    common_hal_canio_message_set_rtr(self, mp_obj_is_true(rtr));
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(canio_message_rtr_set_obj, canio_message_rtr_set);
+
+
+STATIC const mp_obj_property_t canio_message_rtr_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&canio_message_rtr_get_obj,
+              (mp_obj_t)&canio_message_rtr_set_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+
+STATIC const mp_rom_map_elem_t canio_message_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_id), MP_ROM_PTR(&canio_message_id_obj) },
+    { MP_ROM_QSTR(MP_QSTR_data), MP_ROM_PTR(&canio_message_data_obj) },
+    { MP_ROM_QSTR(MP_QSTR_rtr), MP_ROM_PTR(&canio_message_rtr_obj) },
+    { MP_ROM_QSTR(MP_QSTR_extended), MP_ROM_PTR(&canio_message_extended_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(canio_message_locals_dict, canio_message_locals_dict_table);
+
+const mp_obj_type_t canio_message_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Message,
+    .make_new = canio_message_make_new,
+    .locals_dict = (mp_obj_t)&canio_message_locals_dict,
+};
diff --git a/shared-bindings/canio/Message.h b/shared-bindings/canio/Message.h
new file mode 100644
index 000000000..34b632e84
--- /dev/null
+++ b/shared-bindings/canio/Message.h
@@ -0,0 +1,44 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-module/canio/Message.h"
+
+extern const mp_obj_type_t canio_message_type;
+
+void common_hal_canio_message_construct(canio_message_obj_t *self, int id, void *data, size_t size, bool rtr, bool extended);
+const void *common_hal_canio_message_get_data(const canio_message_obj_t *self);
+void common_hal_canio_message_set_data(canio_message_obj_t *self, const void *data, size_t size);
+bool common_hal_canio_message_get_extended(const canio_message_obj_t *self);
+void common_hal_canio_message_set_extended(canio_message_obj_t *self, bool extended);
+int common_hal_canio_message_get_id(const canio_message_obj_t *self);
+void common_hal_canio_message_set_id(canio_message_obj_t *self, int id);
+bool common_hal_canio_message_get_rtr(const canio_message_obj_t *self);
+void common_hal_canio_message_set_rtr(canio_message_obj_t *self, bool rtr);
+size_t common_hal_canio_message_get_size(const canio_message_obj_t *self);
+void common_hal_canio_message_set_size(canio_message_obj_t *self, size_t size);
diff --git a/shared-bindings/canio/__init__.c b/shared-bindings/canio/__init__.c
new file mode 100644
index 000000000..b0b982c95
--- /dev/null
+++ b/shared-bindings/canio/__init__.c
@@ -0,0 +1,124 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+//| """CAN bus access
+//|
+//| The `canio` module contains low level classes to support the CAN bus
+//| protocol.
+//|
+//| CAN and Listener classes change hardware state and should be deinitialized when they
+//| are no longer needed if the program continues after use. To do so, either
+//| call :py:meth:`!deinit` or use a context manager. See
+//| :ref:`lifetime-and-contextmanagers` for more info.
+//|
+//| For example::
+//|
+//|   import canio
+//|   from board import *
+//|
+//|   can = canio.CAN(board.CAN_RX, board.CAN_TX, baudrate=1000000)
+//|   message = canio.Message(id=0x0408, data="adafruit"
+//|   can.write(message))
+//|   can.deinit()
+//|
+//| This example will write the data 'adafruit' onto the CAN bus to any
+//| device listening for message id 0x0408.
+//|
+//| A CAN bus involves a transceiver, which is often a separate chip with a "standby" pin.
+//| If your board has a CAN_STANDBY pin, ensure to set it to an output with the value False
+//| to enable the transceiver.
+//|
+//| Other implementations of the CAN device may exist (for instance, attached
+//| via an SPI bus).  If so their constructor arguments may differ, but
+//| otherwise we encourage implementors to follow the API that the core uses.
+//| """
+//|
+
+#include "py/obj.h"
+#include "py/enum.h"
+
+#include "shared-bindings/canio/__init__.h"
+#include "shared-bindings/canio/CAN.h"
+#include "shared-bindings/canio/Match.h"
+#include "shared-bindings/canio/Message.h"
+#include "shared-bindings/canio/Listener.h"
+
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_ACTIVE, BUS_STATE_ERROR_ACTIVE);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_PASSIVE, BUS_STATE_ERROR_PASSIVE);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_WARNING, BUS_STATE_ERROR_WARNING);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, BUS_OFF, BUS_STATE_OFF);
+
+//| class BusState:
+//|     """The state of the CAN bus"""
+//|
+//|     ERROR_ACTIVE: object
+//|     """The bus is in the normal (active) state"""
+//|
+//|     ERROR_WARNING: object
+//|     """The bus is in the normal (active) state, but a moderate number of errors have occurred recently.
+//|
+//|     NOTE: Not all implementations may use ERROR_WARNING.  Do not rely on seeing ERROR_WARNING before ERROR_PASSIVE."""
+//|
+//|     ERROR_PASSIVE: object
+//|     """The bus is in the passive state due to the number of errors that have occurred recently.
+//|
+//|     This device will acknowledge packets it receives, but cannot transmit messages.
+//|     If additional errors occur, this device may progress to BUS_OFF.
+//|     If it successfully acknowledges other packets on the bus, it can return to ERROR_WARNING or ERROR_ACTIVE and transmit packets.
+//|     """
+//|
+//|     BUS_OFF: object
+//|     """The bus has turned off due to the number of errors that have
+//|     occurred recently.  It must be restarted before it will send or receive
+//|     packets.  This device will neither send or acknowledge packets on the bus."""
+//|
+MAKE_ENUM_MAP(canio_bus_state) {
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_ACTIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_PASSIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_WARNING),
+    MAKE_ENUM_MAP_ENTRY(bus_state, BUS_OFF),
+};
+STATIC MP_DEFINE_CONST_DICT(canio_bus_state_locals_dict, canio_bus_state_locals_table);
+
+MAKE_PRINTER(canio, canio_bus_state);
+
+MAKE_ENUM_TYPE(canio, BusState, canio_bus_state);
+
+STATIC const mp_rom_map_elem_t canio_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_BusState), MP_ROM_PTR(&canio_bus_state_type) },
+    { MP_ROM_QSTR(MP_QSTR_CAN), MP_ROM_PTR(&canio_can_type) },
+    { MP_ROM_QSTR(MP_QSTR_Listener), MP_ROM_PTR(&canio_listener_type) },
+    { MP_ROM_QSTR(MP_QSTR_Match), MP_ROM_PTR(&canio_match_type) },
+    { MP_ROM_QSTR(MP_QSTR_Message), MP_ROM_PTR(&canio_message_type) },
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR__canio) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(canio_module_globals, canio_module_globals_table);
+
+const mp_obj_module_t canio_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&canio_module_globals,
+};
diff --git a/shared-bindings/canio/__init__.h b/shared-bindings/canio/__init__.h
new file mode 100644
index 000000000..e24eba92c
--- /dev/null
+++ b/shared-bindings/canio/__init__.h
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+typedef enum {
+    BUS_STATE_ERROR_ACTIVE, BUS_STATE_ERROR_PASSIVE, BUS_STATE_ERROR_WARNING, BUS_STATE_OFF
+} canio_bus_state_t;
+
+extern const mp_obj_type_t canio_bus_state_type;
diff --git a/shared-module/canio/Match.c b/shared-module/canio/Match.c
new file mode 100644
index 000000000..9e33b956f
--- /dev/null
+++ b/shared-module/canio/Match.c
@@ -0,0 +1,43 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-module/canio/Match.h"
+
+void common_hal_canio_match_construct(canio_match_obj_t *self, int address, int mask, bool extended) {
+    self->address = address;
+    self->mask = mask;
+    self->extended = extended;
+}
+
+int common_hal_canio_match_get_address(const canio_match_obj_t *self) {
+    return self->address;
+}
+int common_hal_canio_match_get_mask(const canio_match_obj_t *self) {
+    return self->mask;
+}
+bool common_hal_canio_match_get_extended(const canio_match_obj_t *self) {
+    return self->extended;
+}
diff --git a/shared-module/canio/Match.h b/shared-module/canio/Match.h
new file mode 100644
index 000000000..25f047f37
--- /dev/null
+++ b/shared-module/canio/Match.h
@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    int address;
+    int mask;
+    bool extended;
+} canio_match_obj_t;
diff --git a/shared-module/canio/Message.c b/shared-module/canio/Message.c
new file mode 100644
index 000000000..b8ebb7859
--- /dev/null
+++ b/shared-module/canio/Message.c
@@ -0,0 +1,101 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-module/canio/Message.h"
+
+#include <string.h>
+
+void common_hal_canio_message_construct(canio_message_obj_t *self, int id, void *data, size_t size, bool rtr, bool extended)
+{
+    self->id = id;
+    self->size = size;
+    self->rtr = rtr;
+    self->extended = extended;
+    if (data) {
+        memcpy(self->data, data, size);
+    } else {
+        memset(self->data, 0, size);
+    }
+}
+
+int common_hal_canio_message_get_id(const canio_message_obj_t *self)
+{
+    return self->id;
+}
+
+void common_hal_canio_message_set_id(canio_message_obj_t *self, int id)
+{
+    self->id = id;
+}
+
+
+const void *common_hal_canio_message_get_data(const canio_message_obj_t *self)
+{
+    return self->data;
+}
+
+const void common_hal_canio_message_set_data(canio_message_obj_t *self, const void *data, size_t size)
+{
+    self->rtr = false;
+    self->size = size;
+    memcpy(self->data, data, size);
+}
+
+
+size_t common_hal_canio_message_get_size(const canio_message_obj_t *self)
+{
+    return self->size;
+}
+
+void common_hal_canio_message_set_size(canio_message_obj_t *self, size_t size)
+{
+    memset(self->data, 0, size);
+    self->size = size;
+}
+
+
+bool common_hal_canio_message_get_rtr(const canio_message_obj_t *self)
+{
+    return self->rtr;
+}
+
+void common_hal_canio_message_set_rtr(canio_message_obj_t *self, bool rtr)
+{
+    self->rtr = rtr;
+    if (rtr) {
+        memset(self->data, 0, self->size);
+    }
+}
+
+bool common_hal_canio_message_get_extended(const canio_message_obj_t *self)
+{
+    return self->extended;
+}
+
+void common_hal_canio_message_set_extended(canio_message_obj_t *self, bool extended)
+{
+    self->extended = extended;
+}
diff --git a/shared-module/canio/Message.h b/shared-module/canio/Message.h
new file mode 100644
index 000000000..b99c5c48e
--- /dev/null
+++ b/shared-module/canio/Message.h
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    int id;
+    uint8_t data[8];
+    size_t size:4;
+    bool rtr:1;
+    bool extended:1;
+} canio_message_obj_t;