Move to ASF4 and introduce SAMD51 support. (#258)3.0.0-alpha.0

* atmel-samd: Remove ASF3. This will break builds.

* atmel-samd: Add ASF4 for the SAMD21 and SAMD51.

* Introduce the supervisor concept to facilitate porting.

The supervisor is the code which runs individual MicroPython VMs. By
splitting it out we make it more consistent and easier to find.

This also adds very basic SAMD21 and SAMD51 support using the
supervisor. Only the REPL currently works.

This begins the work for #178.

13 files changed, 899 insertions, 0 deletions

diff --git a/supervisor/filesystem.h b/supervisor/filesystem.h
new file mode 100644
index 000000000..38923c6f5
--- /dev/null
+++ b/supervisor/filesystem.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_INCLUDED_SUPERVISOR_FILESYSTEM_H
+#define MICROPY_INCLUDED_SUPERVISOR_FILESYSTEM_H
+
+#include <stdbool.h>
+
+void filesystem_init(void);
+void filesystem_flush(void);
+void filesystem_default_writeable(bool writeable);
+bool filesystem_present(void);
+
+#endif  // MICROPY_INCLUDED_SUPERVISOR_FILESYSTEM_H
diff --git a/supervisor/messages/default.h b/supervisor/messages/default.h
new file mode 100644
index 000000000..b69d49537
--- /dev/null
+++ b/supervisor/messages/default.h
@@ -0,0 +1,95 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_SUPERVISOR_MESSAGES_DEFAULT_H
+#define MICROPY_SUPERVISOR_MESSAGES_DEFAULT_H
+
+#ifndef MSG_OUTPUT_SUFFIX
+#define MSG_OUTPUT_SUFFIX " output:\r\n"
+#endif
+
+#ifndef MSG_NEWLINE
+#define MSG_NEWLINE "\r\n"
+#endif
+
+#ifndef MSG_AUTORELOAD_ON
+#define MSG_AUTORELOAD_ON "Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.\r\n"
+#endif
+
+#ifndef MSG_AUTORELOAD_OFF
+#define MSG_AUTORELOAD_OFF "Auto-reload is off.\r\n"
+#endif
+
+#ifndef MSG_SAFE_MODE_ON
+#define MSG_SAFE_MODE_ON "Running in safe mode! Auto-reload is off.\r\n"
+#endif
+
+#ifndef MSG_SAFE_MODE_NO_MAIN
+#define MSG_SAFE_MODE_NO_MAIN "Running in safe mode! Not running saved code.\r\n"
+#endif
+
+#ifndef MSG_SAFE_MODE_USER_REQUESTED
+#define MSG_SAFE_MODE_USER_REQUESTED "You requested starting safe mode by "
+#endif
+
+#ifndef MSG_SAFE_MODE_USER_EXIT
+#define MSG_SAFE_MODE_USER_EXIT "To exit, please reset the board without "
+#endif
+
+#ifndef MSG_BAD_SAFE_MODE
+#define MSG_BAD_SAFE_MODE "You are running in safe mode which means something really bad happened."
+#endif
+
+#ifndef MSG_SAFE_MODE_CRASH
+#define MSG_SAFE_MODE_CRASH "Looks like our core CircuitPython code crashed hard. Whoops!"
+#endif
+
+#ifndef MSG_SAFE_MODE_FILE_ISSUE
+#define MSG_SAFE_MODE_FILE_ISSUE "Please file an issue here with the contents of your CIRCUITPY drive:"
+#endif
+
+#ifndef MSG_SAFE_MODE_ISSUE_LINK
+#define MSG_SAFE_MODE_ISSUE_LINK "https://github.com/adafruit/circuitpython/issues"
+#endif
+
+#ifndef MSG_SAFE_MODE_BROWN_OUT_LINE_1
+#define MSG_SAFE_MODE_BROWN_OUT_LINE_1 "The microcontroller's power dipped. Please make sure your power supply provides"
+#endif
+
+#ifndef MSG_SAFE_MODE_BROWN_OUT_LINE_2
+#define MSG_SAFE_MODE_BROWN_OUT_LINE_2 "enough power for the whole circuit and press reset (after ejecting CIRCUITPY)."
+#endif
+
+#ifndef MSG_WAIT_BEFORE_REPL
+#define MSG_WAIT_BEFORE_REPL "Press any key to enter the REPL. Use CTRL-D to reload."
+#endif
+
+// Be careful, some tools depend on this.
+#ifndef MSG_SOFT_REBOOT
+#define MSG_SOFT_REBOOT "soft reboot"
+#endif
+
+#endif  // MICROPY_SUPERVISOR_MESSAGES_DEFAULT_H
diff --git a/supervisor/messages/en-US.h b/supervisor/messages/en-US.h
new file mode 100644
index 000000000..d31e3b67a
--- /dev/null
+++ b/supervisor/messages/en-US.h
@@ -0,0 +1,35 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_SUPERVISOR_MESSAGES_EN_US_H
+#define MICROPY_SUPERVISOR_MESSAGES_EN_US_H
+
+// Place override messages here.
+
+// Leave this at the bottom.
+#include "supervisor/messages/default.h"
+
+#endif // MICROPY_SUPERVISOR_MESSAGES_EN_US_H
diff --git a/supervisor/port.h b/supervisor/port.h
new file mode 100644
index 000000000..465b5a27d
--- /dev/null
+++ b/supervisor/port.h
@@ -0,0 +1,56 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016-2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_INCLUDED_SUPERVISOR_PORT_H
+#define MICROPY_INCLUDED_SUPERVISOR_PORT_H
+
+#include "py/mpconfig.h"
+
+#ifndef PORT_HEAP_SIZE
+#error "Please define PORT_HEAP_SIZE to specify heap size in bytes."
+#endif
+
+typedef enum {
+  NO_SAFE_MODE = 0,
+  BROWNOUT,
+  HARD_CRASH,
+  USER_SAFE_MODE,
+} safe_mode_t;
+
+// Provided by the linker;
+extern uint32_t _ezero;
+
+// This file defines core methods that must be implemented by a port.
+extern uint32_t _estack;
+
+// Stored at the end of the bss section (which includes the heap).
+extern uint32_t _ebss;
+
+safe_mode_t port_init(void);
+void reset_port(void);
+void reset_board(void);
+
+#endif  // MICROPY_INCLUDED_SUPERVISOR_PORT_H
diff --git a/supervisor/serial.h b/supervisor/serial.h
new file mode 100644
index 000000000..9446ee71c
--- /dev/null
+++ b/supervisor/serial.h
@@ -0,0 +1,39 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_INCLUDED_SUPERVISOR_SERIAL_H
+#define MICROPY_INCLUDED_SUPERVISOR_SERIAL_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+void serial_init(void);
+void serial_write(const char* text);
+char serial_read(void);
+bool serial_bytes_available(void);
+bool serial_connected(void);
+
+#endif  // MICROPY_INCLUDED_SUPERVISOR_SERIAL_H
diff --git a/supervisor/shared/autoreload.c b/supervisor/shared/autoreload.c
new file mode 100644
index 000000000..b1d0f05a9
--- /dev/null
+++ b/supervisor/shared/autoreload.c
@@ -0,0 +1,67 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Scott Shawcroft 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 "autoreload.h"
+
+#include "lib/utils/interrupt_char.h"
+#include "py/mphal.h"
+
+volatile uint32_t autoreload_delay_ms = 0;
+bool autoreload_enabled = false;
+volatile bool reload_next_character = false;
+
+inline void autoreload_tick() {
+    if (autoreload_delay_ms == 0) {
+        return;
+    }
+    if (autoreload_delay_ms == 1 && autoreload_enabled && !reload_next_character) {
+        mp_keyboard_interrupt();
+        reload_next_character = true;
+    }
+    autoreload_delay_ms--;
+}
+
+void autoreload_enable() {
+    autoreload_enabled = true;
+    reload_next_character = false;
+}
+
+void autoreload_disable() {
+    autoreload_enabled = false;
+}
+
+inline bool autoreload_is_enabled() {
+    return autoreload_enabled;
+}
+
+void autoreload_start() {
+    autoreload_delay_ms = CIRCUITPY_AUTORELOAD_DELAY_MS;
+}
+
+void autoreload_stop() {
+    autoreload_delay_ms = 0;
+    reload_next_character = false;
+}
diff --git a/supervisor/shared/autoreload.h b/supervisor/shared/autoreload.h
new file mode 100644
index 000000000..bc3c6d21d
--- /dev/null
+++ b/supervisor/shared/autoreload.h
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_INCLUDED_SUPERVISOR_AUTORELOAD_H
+#define MICROPY_INCLUDED_SUPERVISOR_AUTORELOAD_H
+
+#include <stdbool.h>
+
+extern volatile bool reload_next_character;
+
+void autoreload_tick(void);
+
+void autoreload_start(void);
+void autoreload_stop(void);
+void autoreload_enable(void);
+void autoreload_disable(void);
+bool autoreload_is_enabled(void);
+
+#endif  // MICROPY_INCLUDED_SUPERVISOR_AUTORELOAD_H
diff --git a/supervisor/shared/rgb_led_colors.h b/supervisor/shared/rgb_led_colors.h
new file mode 100644
index 000000000..12f5cc3d9
--- /dev/null
+++ b/supervisor/shared/rgb_led_colors.h
@@ -0,0 +1,34 @@
+#define BLACK   0x000000
+#define GREEN   0x001000
+#define BLUE    0x000010
+#define CYAN    0x001010
+#define RED     0x100000
+#define ORANGE  0x100800
+#define YELLOW  0x101000
+#define PURPLE  0x100010
+#define WHITE   0x101010
+
+#define BOOT_RUNNING BLUE
+#define MAIN_RUNNING GREEN
+#define SAFE_MODE    YELLOW
+#define ALL_DONE     GREEN
+#define REPL_RUNNING WHITE
+
+#define ACTIVE_WRITE 0x200000
+
+#define ALL_GOOD_CYCLE_MS 2000u
+
+#define LINE_NUMBER_TOGGLE_LENGTH 300u
+#define EXCEPTION_TYPE_LENGTH_MS 1000u
+
+#define THOUSANDS WHITE
+#define HUNDREDS  BLUE
+#define TENS      YELLOW
+#define ONES      CYAN
+
+#define INDENTATION_ERROR GREEN
+#define SYNTAX_ERROR      CYAN
+#define NAME_ERROR        WHITE
+#define OS_ERROR          ORANGE
+#define VALUE_ERROR       PURPLE
+#define OTHER_ERROR       YELLOW
diff --git a/supervisor/shared/rgb_led_status.c b/supervisor/shared/rgb_led_status.c
new file mode 100644
index 000000000..15150f18b
--- /dev/null
+++ b/supervisor/shared/rgb_led_status.c
@@ -0,0 +1,316 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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 "mphalport.h"
+#include "common-hal/microcontroller/Pin.h"
+#include "rgb_led_status.h"
+#include "pins.h"
+
+uint8_t rgb_status_brightness = 255;
+#ifdef MICROPY_HW_NEOPIXEL
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/neopixel_write/__init__.h"
+static uint8_t status_neopixel_color[3];
+static digitalio_digitalinout_obj_t status_neopixel;
+#endif
+
+
+#if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+
+static uint8_t status_apa102_color[12] = {0, 0, 0, 0, 0xff, 0, 0, 0};
+#ifdef CIRCUITPY_BITBANG_APA102
+#include "shared-bindings/bitbangio/SPI.h"
+#include "shared-module/bitbangio/types.h"
+static bitbangio_spi_obj_t status_apa102;
+#else
+#include "shared-bindings/busio/SPI.h"
+busio_spi_obj_t status_apa102;
+#endif
+#endif
+
+#if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+static uint32_t current_status_color = 0;
+#endif
+
+void rgb_led_status_init() {
+    #ifdef MICROPY_HW_NEOPIXEL
+        common_hal_digitalio_digitalinout_construct(&status_neopixel, MICROPY_HW_NEOPIXEL);
+        // Pretend we aren't using the pins. digitalio.DigitalInOut
+        // will mark them as used.
+        neopixel_in_use = false;
+        common_hal_digitalio_digitalinout_switch_to_output(&status_neopixel, false, DRIVE_MODE_PUSH_PULL);
+    #endif
+    #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+        #ifdef CIRCUITPY_BITBANG_APA102
+        shared_module_bitbangio_spi_construct(&status_apa102,
+                                              MICROPY_HW_APA102_SCK,
+                                              MICROPY_HW_APA102_MOSI,
+                                              mp_const_none);
+        #else
+        if (status_apa102.current_baudrate > 0) {
+            // Don't use spi_deinit because that leads to infinite
+            // recursion because reset_pin may call
+            // rgb_led_status_init.
+            spi_disable(&status_apa102.spi_master_instance);
+        }
+        common_hal_busio_spi_construct(&status_apa102,
+                                      MICROPY_HW_APA102_SCK,
+                                      MICROPY_HW_APA102_MOSI,
+                                      mp_const_none);
+        #endif
+        // Pretend we aren't using the pins. bitbangio.SPI will
+        // mark them as used.
+        apa102_mosi_in_use = false;
+        apa102_sck_in_use = false;
+        #ifdef CIRCUITPY_BITBANG_APA102
+        shared_module_bitbangio_spi_try_lock(&status_apa102);
+        shared_module_bitbangio_spi_configure(&status_apa102, 100000, 0, 1, 8);
+        #else
+        common_hal_busio_spi_try_lock(&status_apa102);
+        common_hal_busio_spi_configure(&status_apa102, 100000, 0, 1, 8);
+        #endif
+    #endif
+
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+    // Force a write of the current status color.
+    uint32_t rgb = current_status_color;
+    current_status_color = 0;
+    new_status_color(rgb);
+    #endif
+}
+
+void reset_status_led() {
+    #ifdef MICROPY_HW_NEOPIXEL
+        reset_pin(MICROPY_HW_NEOPIXEL->pin);
+    #endif
+    #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+        reset_pin(MICROPY_HW_APA102_MOSI->pin);
+        reset_pin(MICROPY_HW_APA102_SCK->pin);
+    #endif
+}
+
+void new_status_color(uint32_t rgb) {
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+    if (current_status_color == rgb) {
+        return;
+    }
+    uint32_t rgb_adjusted = color_brightness(rgb, rgb_status_brightness);
+    current_status_color = rgb_adjusted;
+    #endif
+
+    #ifdef MICROPY_HW_NEOPIXEL
+        if (neopixel_in_use) {
+            return;
+        }
+        status_neopixel_color[0] = (rgb_adjusted >> 8) & 0xff;
+        status_neopixel_color[1] = (rgb_adjusted >> 16) & 0xff;
+        status_neopixel_color[2] = rgb_adjusted & 0xff;
+        common_hal_neopixel_write(&status_neopixel, status_neopixel_color, 3);
+    #endif
+    #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+        if (apa102_mosi_in_use || apa102_sck_in_use) {
+            return;
+        }
+        status_apa102_color[5] = rgb_adjusted & 0xff;
+        status_apa102_color[6] = (rgb_adjusted >> 8) & 0xff;
+        status_apa102_color[7] = (rgb_adjusted >> 16) & 0xff;
+
+        #ifdef CIRCUITPY_BITBANG_APA102
+        shared_module_bitbangio_spi_write(&status_apa102, status_apa102_color, 8);
+        #else
+        common_hal_busio_spi_write(&status_apa102, status_apa102_color, 8);
+        #endif
+    #endif
+}
+
+void temp_status_color(uint32_t rgb) {
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+      uint32_t rgb_adjusted = rgb;
+      rgb_adjusted = color_brightness(rgb, rgb_status_brightness);
+    #endif
+    #ifdef MICROPY_HW_NEOPIXEL
+        if (neopixel_in_use) {
+            return;
+        }
+        uint8_t colors[3] = {(rgb_adjusted >> 8) & 0xff, (rgb_adjusted >> 16) & 0xff, rgb_adjusted & 0xff};
+        common_hal_neopixel_write(&status_neopixel, colors, 3);
+    #endif
+    #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+        if (apa102_mosi_in_use || apa102_sck_in_use) {
+            return;
+        }
+        uint8_t colors[12] = {0, 0, 0, 0, 0xff, rgb_adjusted & 0xff, (rgb_adjusted >> 8) & 0xff, (rgb_adjusted >> 16) & 0xff, 0x0, 0x0, 0x0, 0x0};
+        #ifdef CIRCUITPY_BITBANG_APA102
+        shared_module_bitbangio_spi_write(&status_apa102, colors, 12);
+        #else
+        common_hal_busio_spi_write(&status_apa102, colors, 12);
+        #endif
+    #endif
+}
+
+void clear_temp_status() {
+    #ifdef MICROPY_HW_NEOPIXEL
+        common_hal_neopixel_write(&status_neopixel, status_neopixel_color, 3);
+    #endif
+    #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
+        #ifdef CIRCUITPY_BITBANG_APA102
+        shared_module_bitbangio_spi_write(&status_apa102, status_apa102_color, 8);
+        #else
+        common_hal_busio_spi_write(&status_apa102, status_apa102_color, 8);
+        #endif
+    #endif
+}
+
+uint32_t color_brightness(uint32_t color, uint8_t brightness) {
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+    uint32_t result = ((color & 0xff0000) * brightness / 255) & 0xff0000;
+    result += ((color & 0xff00) * brightness / 255) & 0xff00;
+    result += ((color & 0xff) * brightness / 255) & 0xff;
+    return result;
+    #else
+    return color;
+    #endif
+}
+
+void set_rgb_status_brightness(uint8_t level){
+      rgb_status_brightness = level;
+}
+
+void prep_rgb_status_animation(const pyexec_result_t* result, bool found_main, rgb_status_animation_t* status) {
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+    new_status_color(ALL_DONE);
+    status->pattern_start = ticks_ms;
+
+    uint32_t total_exception_cycle = 0;
+    status->ones = result->exception_line % 10;
+    status->ones += status->ones > 0 ? 1 : 0;
+    status->tens = (result->exception_line / 10) % 10;
+    status->tens += status->tens > 0 ? 1 : 0;
+    status->hundreds = (result->exception_line / 100) % 10;
+    status->hundreds += status->hundreds > 0 ? 1 : 0;
+    status->thousands = (result->exception_line / 1000) % 10;
+    status->thousands += status->thousands > 0 ? 1 : 0;
+    status->digit_sum = status->ones + status->tens + status->hundreds + status->thousands;
+    uint8_t num_places = 0;
+    uint16_t line = result->exception_line;
+    for (int i = 0; i < 4; i++) {
+        if ((line % 10) > 0) {
+            num_places++;
+        }
+        line /= 10;
+    }
+    status->ok = result->return_code != PYEXEC_EXCEPTION;
+    if (!status->ok) {
+        status->total_exception_cycle = EXCEPTION_TYPE_LENGTH_MS * 3 + LINE_NUMBER_TOGGLE_LENGTH * digit_sum + LINE_NUMBER_TOGGLE_LENGTH * num_places;
+    }
+    if (mp_obj_is_subclass_fast(result->exception_type, &mp_type_IndentationError)) {
+        status->exception_color = INDENTATION_ERROR;
+    } else if (mp_obj_is_subclass_fast(result->exception_type, &mp_type_SyntaxError)) {
+        status->exception_color = SYNTAX_ERROR;
+    } else if (mp_obj_is_subclass_fast(result->exception_type, &mp_type_NameError)) {
+        status->exception_color = NAME_ERROR;
+    } else if (mp_obj_is_subclass_fast(result->exception_type, &mp_type_OSError)) {
+        status->exception_color = OS_ERROR;
+    } else if (mp_obj_is_subclass_fast(result->exception_type, &mp_type_ValueError)) {
+        status->exception_color = VALUE_ERROR;
+    } else {
+        status->exception_color = OTHER_ERROR;
+    }
+    #endif
+}
+
+void tick_rgb_status_animation(rgb_status_animation_t* status) {
+    #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK))
+    uint32_t tick_diff = ticks_ms - pattern_start;
+    if (status->ok) {
+        // All is good. Ramp ALL_DONE up and down.
+        if (tick_diff > ALL_GOOD_CYCLE_MS) {
+            pattern_start = ticks_ms;
+            tick_diff = 0;
+        }
+
+        uint16_t brightness = tick_diff * 255 / (ALL_GOOD_CYCLE_MS / 2);
+        if (brightness > 255) {
+            brightness = 511 - brightness;
+        }
+        if (safe_mode == NO_SAFE_MODE) {
+            new_status_color(color_brightness(ALL_DONE, brightness));
+        } else {
+            new_status_color(color_brightness(SAFE_MODE, brightness));
+        }
+    } else {
+        if (tick_diff > total_exception_cycle) {
+            pattern_start = ticks_ms;
+            tick_diff = 0;
+        }
+        // First flash the file color.
+        if (tick_diff < EXCEPTION_TYPE_LENGTH_MS) {
+            if (status->found_main) {
+                new_status_color(MAIN_RUNNING);
+            } else {
+                new_status_color(BOOT_RUNNING);
+            }
+        // Next flash the exception color.
+        } else if (tick_diff < EXCEPTION_TYPE_LENGTH_MS * 2) {
+            new_status_color(exception_color);
+        // Finally flash the line number digits from highest to lowest.
+        // Zeroes will not produce a flash but can be read by the absence of
+        // a color from the sequence.
+        } else if (tick_diff < (EXCEPTION_TYPE_LENGTH_MS * 2 + LINE_NUMBER_TOGGLE_LENGTH * digit_sum)) {
+            uint32_t digit_diff = tick_diff - EXCEPTION_TYPE_LENGTH_MS * 2;
+            if ((digit_diff % LINE_NUMBER_TOGGLE_LENGTH) < (LINE_NUMBER_TOGGLE_LENGTH / 2)) {
+                new_status_color(BLACK);
+            } else if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * thousands) {
+                if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH) {
+                    new_status_color(BLACK);
+                } else {
+                    new_status_color(THOUSANDS);
+                }
+            } else if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * (thousands + hundreds)) {
+                if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * (thousands + 1)) {
+                    new_status_color(BLACK);
+                } else {
+                    new_status_color(HUNDREDS);
+                }
+            } else if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * (thousands + hundreds + tens)) {
+                if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * (thousands + hundreds + 1)) {
+                    new_status_color(BLACK);
+                } else {
+                    new_status_color(TENS);
+                }
+            } else {
+                if (digit_diff < LINE_NUMBER_TOGGLE_LENGTH * (thousands + hundreds + tens + 1)) {
+                    new_status_color(BLACK);
+                } else {
+                    new_status_color(ONES);
+                }
+            }
+        } else {
+            new_status_color(BLACK);
+        }
+    }
+    #endif
+}
diff --git a/supervisor/shared/rgb_led_status.h b/supervisor/shared/rgb_led_status.h
new file mode 100644
index 000000000..2ea00f4fe
--- /dev/null
+++ b/supervisor/shared/rgb_led_status.h
@@ -0,0 +1,73 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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.
+ */
+
+#ifndef MICROPY_INCLUDED_SUPERVISOR_RGB_LED_STATUS_H
+#define MICROPY_INCLUDED_SUPERVISOR_RGB_LED_STATUS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "lib/utils/pyexec.h"
+
+#include "mpconfigport.h"
+#include "rgb_led_colors.h"
+
+// Overall, the time module must be implemented.
+// To work with a DotStar, one must have MICROPY_HW_APA102_SCK and
+// MICROPY_HW_APA102_MOSI defined and bitbangio.SPI or busio.SPI implemented.
+// To work with a NeoPixel, one must have MICROPY_HW_NEOPIXEL defined and
+// neopixel_write implemented.
+
+#if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK) && !defined(CIRCUITPY_BITBANG_APA102)
+#include "common-hal/busio/SPI.h"
+extern busio_spi_obj_t status_apa102;
+#endif
+
+void rgb_led_status_init(void);
+void reset_status_led(void);
+void new_status_color(uint32_t rgb);
+void temp_status_color(uint32_t rgb);
+void clear_temp_status(void);
+
+uint32_t color_brightness(uint32_t color, uint8_t brightness);
+void set_rgb_status_brightness(uint8_t level);
+
+typedef struct {
+    bool ok;
+    uint32_t pattern_start;
+    uint32_t total_exception_cycle;
+    uint8_t ones;
+    uint8_t tens;
+    uint8_t hundreds;
+    uint8_t thousands;
+    uint32_t exception_color;
+    bool found_main;
+} rgb_status_animation_t;
+
+void prep_rgb_status_animation(const pyexec_result_t* result, bool found_main, rgb_status_animation_t* status);
+void tick_rgb_status_animation(rgb_status_animation_t* status);
+
+#endif  // MICROPY_INCLUDED_SUPERVISOR_RGB_LED_STATUS_H
diff --git a/supervisor/stub/filesystem.c b/supervisor/stub/filesystem.c
new file mode 100644
index 000000000..462ee62a4
--- /dev/null
+++ b/supervisor/stub/filesystem.c
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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 "supervisor/filesystem.h"
+
+void filesystem_init(void) {
+}
+
+void filesystem_flush(void) {
+}
+
+void filesystem_default_writeable(bool writeable) {
+}
+
+bool filesystem_present(void) {
+    return false;
+}
diff --git a/supervisor/stub/serial.c b/supervisor/stub/serial.c
new file mode 100644
index 000000000..4f0e11873
--- /dev/null
+++ b/supervisor/stub/serial.c
@@ -0,0 +1,46 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft 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 "supervisor/serial.h"
+
+void serial_init(void) {
+
+}
+
+bool serial_connected(void) {
+    return false;
+}
+
+char serial_read(void) {
+    return 0;
+}
+
+bool serial_bytes_available(void) {
+    return false;
+}
+
+void serial_write(const char* text) {
+}
diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
new file mode 100644
index 000000000..f67439a97
--- /dev/null
+++ b/supervisor/supervisor.mk
@@ -0,0 +1,19 @@
+SRC_SUPERVISOR = \
+	main.c \
+	supervisor/port.c \
+	supervisor/shared/autoreload.c \
+	supervisor/shared/rgb_led_status.c
+
+ifeq ($(wildcard supervisor/filesystem.c),)
+	SRC_SUPERVISOR += supervisor/filesystem.c
+else
+	SRC_SUPERVISOR += supervisor/stub/filesystem.c
+endif
+
+ifeq ($(wildcard atmel-samd/supervisor/serial.c),)
+	SRC_SUPERVISOR += supervisor/serial.c
+else
+	SRC_SUPERVISOR += supervisor/stub/serial.c
+endif
+
+SUPERVISOR_O = $(addprefix $(BUILD)/, $(SRC_SUPERVISOR:.c=.o))