nrf: add support for nrf52833

This adds preliminary support for the nRF52833, which is a variant of
the nRF52840 with half the RAM, half the flash, and fewer peripherals.

Signed-off-by: Sean Cross <sean@xobs.io>

12 files changed, 437 insertions, 6 deletions

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 89d88ce36..876628342 100755
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -182,6 +182,11 @@ SRC_C += \
 	lib/tinyusb/src/portable/nordic/nrf5x/dcd_nrf5x.c
 endif
 
+ifeq ($(MCU_SUB_VARIANT),nrf52833)
+SRC_C += \
+	lib/tinyusb/src/portable/nordic/nrf5x/dcd_nrf5x.c
+endif
+
 ifeq ($(CIRCUITPY_NETWORK),1)
 CFLAGS += -DMICROPY_PY_NETWORK=1
 
diff --git a/ports/nrf/boards/common.template.ld b/ports/nrf/boards/common.template.ld
index 2fca16707..a2bbf0ec8 100644
--- a/ports/nrf/boards/common.template.ld
+++ b/ports/nrf/boards/common.template.ld
@@ -5,7 +5,7 @@
 /* Specify the memory areas */
 MEMORY
 {
-    FLASH (rx)      : ORIGIN = 0x00000000, LENGTH = 0x100000 /* entire flash, 1 MiB */
+    FLASH (rx)      : ORIGIN = 0x00000000, LENGTH = ${FLASH_SIZE} /* entire flash */
     /* nRF SoftDevice */
     FLASH_MBR (rx)  : ORIGIN = ${MBR_START_ADDR}, LENGTH = ${MBR_SIZE}
     FLASH_SD (rx)   : ORIGIN = ${SD_FLASH_START_ADDR}, LENGTH = ${SD_FLASH_SIZE}
@@ -23,7 +23,7 @@ MEMORY
     /* To measure the minimum required amount of memory for given configuration, set this number
        high enough to work and then check the mutation of the value done by sd_ble_enable. */
     SPIM3_RAM (rw)  : ORIGIN = 0x20000000 + ${SOFTDEVICE_RAM_SIZE}, LENGTH = ${SPIM3_BUFFER_SIZE}
-    RAM (xrw)       : ORIGIN = 0x20000000 + ${SOFTDEVICE_RAM_SIZE} + ${SPIM3_BUFFER_SIZE}, LENGTH = 256K - ${SOFTDEVICE_RAM_SIZE} -${SPIM3_BUFFER_SIZE}
+    RAM (xrw)       : ORIGIN = 0x20000000 + ${SOFTDEVICE_RAM_SIZE} + ${SPIM3_BUFFER_SIZE}, LENGTH = ${RAM_SIZE} - ${SOFTDEVICE_RAM_SIZE} -${SPIM3_BUFFER_SIZE}
 
 }
 
diff --git a/ports/nrf/common-hal/microcontroller/__init__.c b/ports/nrf/common-hal/microcontroller/__init__.c
index 7eb1c0614..90d97f868 100644
--- a/ports/nrf/common-hal/microcontroller/__init__.c
+++ b/ports/nrf/common-hal/microcontroller/__init__.c
@@ -168,5 +168,17 @@ STATIC const mp_rom_map_elem_t mcu_pin_globals_table[] = {
   { MP_ROM_QSTR(MP_QSTR_P1_14), MP_ROM_PTR(&pin_P1_14) },
   { MP_ROM_QSTR(MP_QSTR_P1_15), MP_ROM_PTR(&pin_P1_15) },
 #endif
+#ifdef NRF52833
+  { MP_ROM_QSTR(MP_QSTR_P1_00), MP_ROM_PTR(&pin_P1_00) },
+  { MP_ROM_QSTR(MP_QSTR_P1_01), MP_ROM_PTR(&pin_P1_01) },
+  { MP_ROM_QSTR(MP_QSTR_P1_02), MP_ROM_PTR(&pin_P1_02) },
+  { MP_ROM_QSTR(MP_QSTR_P1_03), MP_ROM_PTR(&pin_P1_03) },
+  { MP_ROM_QSTR(MP_QSTR_P1_04), MP_ROM_PTR(&pin_P1_04) },
+  { MP_ROM_QSTR(MP_QSTR_P1_05), MP_ROM_PTR(&pin_P1_05) },
+  { MP_ROM_QSTR(MP_QSTR_P1_06), MP_ROM_PTR(&pin_P1_06) },
+  { MP_ROM_QSTR(MP_QSTR_P1_07), MP_ROM_PTR(&pin_P1_07) },
+  { MP_ROM_QSTR(MP_QSTR_P1_08), MP_ROM_PTR(&pin_P1_08) },
+  { MP_ROM_QSTR(MP_QSTR_P1_09), MP_ROM_PTR(&pin_P1_09) },
+#endif
 };
 MP_DEFINE_CONST_DICT(mcu_pin_globals, mcu_pin_globals_table);
diff --git a/ports/nrf/device/nrf52/startup_nrf52833.c b/ports/nrf/device/nrf52/startup_nrf52833.c
new file mode 100644
index 000000000..ad875dcee
--- /dev/null
+++ b/ports/nrf/device/nrf52/startup_nrf52833.c
@@ -0,0 +1,184 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Glenn Ruben Bakke
+ *
+ * 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 <stdint.h>
+
+extern uint32_t _estack;
+extern uint32_t _sidata;
+extern uint32_t _sdata;
+extern uint32_t _edata;
+extern uint32_t _sbss;
+extern uint32_t _ebss;
+
+typedef void (*func)(void);
+
+#define _start   main
+
+extern void  _start(void) __attribute__((noreturn));
+extern void SystemInit(void);
+
+void Default_Handler(void) {
+    while (1);
+}
+
+void Reset_Handler(void) {
+    uint32_t * p_src  = &_sidata;
+    uint32_t * p_dest = &_sdata;
+
+    while (p_dest < &_edata) {
+      *p_dest++ = *p_src++;
+    }
+
+    uint32_t * p_bss     = &_sbss;
+    uint32_t * p_bss_end = &_ebss;
+    while (p_bss < p_bss_end) {
+        *p_bss++ = 0ul;
+    }
+
+    SystemInit();
+    _start();
+}
+
+void NMI_Handler                 (void) __attribute__ ((weak, alias("Default_Handler")));
+void HardFault_Handler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void MemoryManagement_Handler    (void) __attribute__ ((weak, alias("Default_Handler")));
+void BusFault_Handler            (void) __attribute__ ((weak, alias("Default_Handler")));
+void UsageFault_Handler          (void) __attribute__ ((weak, alias("Default_Handler")));
+void SVC_Handler                 (void) __attribute__ ((weak, alias("Default_Handler")));
+void DebugMon_Handler            (void) __attribute__ ((weak, alias("Default_Handler")));
+void PendSV_Handler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void SysTick_Handler             (void) __attribute__ ((weak, alias("Default_Handler")));
+
+void POWER_CLOCK_IRQHandler      (void) __attribute__ ((weak, alias("Default_Handler")));
+void RADIO_IRQHandler            (void) __attribute__ ((weak, alias("Default_Handler")));
+void UARTE0_UART0_IRQHandler     (void) __attribute__ ((weak, alias("Default_Handler")));
+void SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQHandler (void) __attribute__ ((weak, alias("Default_Handler")));
+void SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQHandler (void) __attribute__ ((weak, alias("Default_Handler")));
+void NFCT_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void GPIOTE_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void SAADC_IRQHandler            (void) __attribute__ ((weak, alias("Default_Handler")));
+void TIMER0_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void TIMER1_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void TIMER2_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void RTC0_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void TEMP_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void RNG_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void ECB_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void CCM_AAR_IRQHandler          (void) __attribute__ ((weak, alias("Default_Handler")));
+void WDT_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void RTC1_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void QDEC_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void COMP_LPCOMP_IRQHandler      (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI0_EGU0_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI1_EGU1_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI2_EGU2_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI3_EGU3_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI4_EGU4_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void SWI5_EGU5_IRQHandler        (void) __attribute__ ((weak, alias("Default_Handler")));
+void TIMER3_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void TIMER4_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void PWM0_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void PDM_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void MWU_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void PWM1_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void PWM2_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void SPIM2_SPIS2_SPI2_IRQHandler (void) __attribute__ ((weak, alias("Default_Handler")));
+void RTC2_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void I2S_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void FPU_IRQHandler              (void) __attribute__ ((weak, alias("Default_Handler")));
+void USBD_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void UARTE1_IRQHandler           (void) __attribute__ ((weak, alias("Default_Handler")));
+void PWM3_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
+void SPIM3_IRQHandler            (void) __attribute__ ((weak, alias("Default_Handler")));
+
+const func __Vectors[] __attribute__ ((used, section(".isr_vector"))) = {
+    (func)&_estack,
+    Reset_Handler,
+    NMI_Handler,
+    HardFault_Handler,
+    MemoryManagement_Handler,
+    BusFault_Handler,
+    UsageFault_Handler,
+    0,
+    0,
+    0,
+    0,
+    SVC_Handler,
+    DebugMon_Handler,
+    0,
+    PendSV_Handler,
+    SysTick_Handler,
+
+    /* External Interrupts */
+    POWER_CLOCK_IRQHandler,
+    RADIO_IRQHandler,
+    UARTE0_UART0_IRQHandler,
+    SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQHandler,
+    SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQHandler,
+    NFCT_IRQHandler,
+    GPIOTE_IRQHandler,
+    SAADC_IRQHandler,
+    TIMER0_IRQHandler,
+    TIMER1_IRQHandler,
+    TIMER2_IRQHandler,
+    RTC0_IRQHandler,
+    TEMP_IRQHandler,
+    RNG_IRQHandler,
+    ECB_IRQHandler,
+    CCM_AAR_IRQHandler,
+    WDT_IRQHandler,
+    RTC1_IRQHandler,
+    QDEC_IRQHandler,
+    COMP_LPCOMP_IRQHandler,
+    SWI0_EGU0_IRQHandler,
+    SWI1_EGU1_IRQHandler,
+    SWI2_EGU2_IRQHandler,
+    SWI3_EGU3_IRQHandler,
+    SWI4_EGU4_IRQHandler,
+    SWI5_EGU5_IRQHandler,
+    TIMER3_IRQHandler,
+    TIMER4_IRQHandler,
+    PWM0_IRQHandler,
+    PDM_IRQHandler,
+    0,
+    0,
+    MWU_IRQHandler,
+    PWM1_IRQHandler,
+    PWM2_IRQHandler,
+    SPIM2_SPIS2_SPI2_IRQHandler,
+    RTC2_IRQHandler,
+    I2S_IRQHandler,
+    FPU_IRQHandler,
+    USBD_IRQHandler,
+    UARTE1_IRQHandler,
+    0,
+    0,
+    0,
+    0,
+    PWM3_IRQHandler,
+    0,
+    SPIM3_IRQHandler,
+};
diff --git a/ports/nrf/ld_defines.c b/ports/nrf/ld_defines.c
index ebe9c4929..8430daccb 100644
--- a/ports/nrf/ld_defines.c
+++ b/ports/nrf/ld_defines.c
@@ -9,6 +9,9 @@
 // The next line is a marker to start looking for definitions. Lines above the next line are ignored.
 // START_LD_DEFINES
 
+/*FLASH_SIZE=*/                                     FLASH_SIZE;
+/*RAM_SIZE=*/                                       RAM_SIZE;
+
 /*MBR_START_ADDR=*/                                 MBR_START_ADDR;
 /*MBR_SIZE=*/                                       MBR_SIZE;
 
diff --git a/ports/nrf/mpconfigport.h b/ports/nrf/mpconfigport.h
index 44e51fc5f..464a0b3bd 100644
--- a/ports/nrf/mpconfigport.h
+++ b/ports/nrf/mpconfigport.h
@@ -41,6 +41,16 @@
 #ifdef NRF52840
 #define MICROPY_PY_SYS_PLATFORM "nRF52840"
 #define FLASH_SIZE                  (0x100000)  // 1MiB
+#define RAM_SIZE                    (0x40000)   // 256 KiB
+// Special RAM area for SPIM3 transmit buffer, to work around hardware bug.
+// See common.template.ld.
+#define SPIM3_BUFFER_SIZE           (8192)
+#endif
+
+#ifdef NRF52833
+#define MICROPY_PY_SYS_PLATFORM "nRF52833"
+#define FLASH_SIZE                  (0x80000)  // 512 KiB
+#define RAM_SIZE                    (0x20000)  // 128 KiB
 // Special RAM area for SPIM3 transmit buffer, to work around hardware bug.
 // See common.template.ld.
 #define SPIM3_BUFFER_SIZE           (8192)
@@ -112,14 +122,15 @@
 // Define these regions starting down from the bootloader:
 
 // Bootloader values from https://github.com/adafruit/Adafruit_nRF52_Bootloader/blob/master/src/linker/s140_v6.ld
-#define BOOTLOADER_START_ADDR          (0x000F4000)
+#define BOOTLOADER_START_ADDR          (FLASH_SIZE - BOOTLOADER_SIZE - BOOTLOADER_SETTINGS_SIZE - BOOTLOADER_MBR_SIZE)
+#define BOOTLOADER_MBR_SIZE            (0x1000)     // 4kib
 #define BOOTLOADER_SIZE                (0xA000)     // 40kiB
-#define BOOTLOADER_SETTINGS_START_ADDR (0x000FF000)
+#define BOOTLOADER_SETTINGS_START_ADDR (FLASH_SIZE - BOOTLOADER_SETTINGS_SIZE)
 #define BOOTLOADER_SETTINGS_SIZE       (0x1000)     // 4kiB
 
 #define CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_START_ADDR (BOOTLOADER_START_ADDR - CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_SIZE)
 
-#if CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_SIZE > 0 && CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_START_ADDR != (BOOTLOADER_START_ADDR - 256*1024)
+#if CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_SIZE > 0 && CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_START_ADDR != (BOOTLOADER_START_ADDR - CIRCUITPY_INTERNAL_FLASH_FILESYSTEM_SIZE)
 #warning Internal flash filesystem location has moved!
 #endif
 
diff --git a/ports/nrf/mpconfigport.mk b/ports/nrf/mpconfigport.mk
index 342f1384a..e483d455e 100644
--- a/ports/nrf/mpconfigport.mk
+++ b/ports/nrf/mpconfigport.mk
@@ -73,4 +73,18 @@ NRF_DEFINES += -DNRF52840_XXAA -DNRF52840
 CFLAGS += -DCONFIG_NFCT_PINS_AS_GPIOS
 
 CIRCUITPY_ULAB = 1
+
+else
+ifeq ($(MCU_CHIP),nrf52833)
+MCU_SERIES = m4
+MCU_VARIANT = nrf52
+MCU_SUB_VARIANT = nrf52833
+
+SD ?= s140
+SOFTDEV_VERSION ?= 6.1.0
+
+BOOT_SETTING_ADDR = 0x7F000
+NRF_DEFINES += -DNRF52833_XXAA -DNRF52833
+
+endif
 endif
diff --git a/ports/nrf/nrfx_config.h b/ports/nrf/nrfx_config.h
index a13ddf018..05ec95ae3 100644
--- a/ports/nrf/nrfx_config.h
+++ b/ports/nrf/nrfx_config.h
@@ -41,7 +41,7 @@
 #define NRFX_SPIM1_ENABLED 1
 #endif
 #define NRFX_SPIM2_ENABLED 1
-#ifdef NRF52840_XXAA
+#if defined(NRF52840_XXAA) || defined(NRF52833_XXAA)
     #define NRFX_SPIM_EXTENDED_ENABLED 1
     #define NRFX_SPIM3_ENABLED 1
 #elif CIRCUITPY_NRF_NUM_I2C == 2
@@ -53,7 +53,9 @@
 #define NRFX_SPIM_MISO_PULL_CFG 1
 
 // QSPI
+#if defined(NRF52840_XXAA)
 #define NRFX_QSPI_ENABLED                          1
+#endif
 
 // TWI aka. I2C; always enable TWIM0 (no conflict with SPIM1 and SPIM2)
 #if CIRCUITPY_NRF_NUM_I2C == 1 || CIRCUITPY_NRF_NUM_I2C == 2
diff --git a/ports/nrf/peripherals/nrf/nrf52833/pins.c b/ports/nrf/peripherals/nrf/nrf52833/pins.c
new file mode 100644
index 000000000..cdd4959cb
--- /dev/null
+++ b/ports/nrf/peripherals/nrf/nrf52833/pins.c
@@ -0,0 +1,72 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Dan Halbert 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/obj.h"
+#include "py/mphal.h"
+#include "nrf/pins.h"
+
+const mcu_pin_obj_t pin_P0_00 = PIN(P0_00, 0, 0, 0);
+const mcu_pin_obj_t pin_P0_01 = PIN(P0_01, 0, 1, 0);
+const mcu_pin_obj_t pin_P0_02 = PIN(P0_02, 0, 2, SAADC_CH_PSELP_PSELP_AnalogInput0);
+const mcu_pin_obj_t pin_P0_03 = PIN(P0_03, 0, 3, SAADC_CH_PSELP_PSELP_AnalogInput1);
+const mcu_pin_obj_t pin_P0_04 = PIN(P0_04, 0, 4, SAADC_CH_PSELP_PSELP_AnalogInput2);
+const mcu_pin_obj_t pin_P0_05 = PIN(P0_05, 0, 5, SAADC_CH_PSELP_PSELP_AnalogInput3);
+const mcu_pin_obj_t pin_P0_06 = PIN(P0_06, 0, 6, 0);
+const mcu_pin_obj_t pin_P0_07 = PIN(P0_07, 0, 7, 0);
+const mcu_pin_obj_t pin_P0_08 = PIN(P0_08, 0, 8, 0);
+const mcu_pin_obj_t pin_P0_09 = PIN(P0_09, 0, 9, 0);
+const mcu_pin_obj_t pin_P0_10 = PIN(P0_10, 0, 10, 0);
+const mcu_pin_obj_t pin_P0_11 = PIN(P0_11, 0, 11, 0);
+const mcu_pin_obj_t pin_P0_12 = PIN(P0_12, 0, 12, 0);
+const mcu_pin_obj_t pin_P0_13 = PIN(P0_13, 0, 13, 0);
+const mcu_pin_obj_t pin_P0_14 = PIN(P0_14, 0, 14, 0);
+const mcu_pin_obj_t pin_P0_15 = PIN(P0_15, 0, 15, 0);
+const mcu_pin_obj_t pin_P0_16 = PIN(P0_16, 0, 16, 0);
+const mcu_pin_obj_t pin_P0_17 = PIN(P0_17, 0, 17, 0);
+const mcu_pin_obj_t pin_P0_18 = PIN(P0_18, 0, 18, 0);
+const mcu_pin_obj_t pin_P0_19 = PIN(P0_19, 0, 19, 0);
+const mcu_pin_obj_t pin_P0_20 = PIN(P0_20, 0, 20, 0);
+const mcu_pin_obj_t pin_P0_21 = PIN(P0_21, 0, 21, 0);
+const mcu_pin_obj_t pin_P0_22 = PIN(P0_22, 0, 22, 0);
+const mcu_pin_obj_t pin_P0_23 = PIN(P0_23, 0, 23, 0);
+const mcu_pin_obj_t pin_P0_24 = PIN(P0_24, 0, 24, 0);
+const mcu_pin_obj_t pin_P0_25 = PIN(P0_25, 0, 25, 0);
+const mcu_pin_obj_t pin_P0_26 = PIN(P0_26, 0, 26, 0);
+const mcu_pin_obj_t pin_P0_27 = PIN(P0_27, 0, 27, 0);
+const mcu_pin_obj_t pin_P0_28 = PIN(P0_28, 0, 28, SAADC_CH_PSELP_PSELP_AnalogInput4);
+const mcu_pin_obj_t pin_P0_29 = PIN(P0_29, 0, 29, SAADC_CH_PSELP_PSELP_AnalogInput5);
+const mcu_pin_obj_t pin_P0_30 = PIN(P0_30, 0, 30, SAADC_CH_PSELP_PSELP_AnalogInput6);
+const mcu_pin_obj_t pin_P0_31 = PIN(P0_31, 0, 31, SAADC_CH_PSELP_PSELP_AnalogInput7);
+const mcu_pin_obj_t pin_P1_00 = PIN(P1_00, 1, 0, 0);
+const mcu_pin_obj_t pin_P1_01 = PIN(P1_01, 1, 1, 0);
+const mcu_pin_obj_t pin_P1_02 = PIN(P1_02, 1, 2, 0);
+const mcu_pin_obj_t pin_P1_03 = PIN(P1_03, 1, 3, 0);
+const mcu_pin_obj_t pin_P1_04 = PIN(P1_04, 1, 4, 0);
+const mcu_pin_obj_t pin_P1_05 = PIN(P1_05, 1, 5, 0);
+const mcu_pin_obj_t pin_P1_06 = PIN(P1_06, 1, 6, 0);
+const mcu_pin_obj_t pin_P1_07 = PIN(P1_07, 1, 7, 0);
+const mcu_pin_obj_t pin_P1_08 = PIN(P1_08, 1, 8, 0);
+const mcu_pin_obj_t pin_P1_09 = PIN(P1_09, 1, 9, 0);
diff --git a/ports/nrf/peripherals/nrf/nrf52833/pins.h b/ports/nrf/peripherals/nrf/nrf52833/pins.h
new file mode 100644
index 000000000..44baa315b
--- /dev/null
+++ b/ports/nrf/peripherals/nrf/nrf52833/pins.h
@@ -0,0 +1,73 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 by Dan Halbert 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_NRF_PERIPHERALS_NRF52833_PINS_H
+#define MICROPY_INCLUDED_NRF_PERIPHERALS_NRF52833_PINS_H
+
+extern const mcu_pin_obj_t pin_P0_00;
+extern const mcu_pin_obj_t pin_P0_01;
+extern const mcu_pin_obj_t pin_P0_02;
+extern const mcu_pin_obj_t pin_P0_03;
+extern const mcu_pin_obj_t pin_P0_04;
+extern const mcu_pin_obj_t pin_P0_05;
+extern const mcu_pin_obj_t pin_P0_06;
+extern const mcu_pin_obj_t pin_P0_07;
+extern const mcu_pin_obj_t pin_P0_08;
+extern const mcu_pin_obj_t pin_P0_09;
+extern const mcu_pin_obj_t pin_P0_10;
+extern const mcu_pin_obj_t pin_P0_11;
+extern const mcu_pin_obj_t pin_P0_12;
+extern const mcu_pin_obj_t pin_P0_13;
+extern const mcu_pin_obj_t pin_P0_14;
+extern const mcu_pin_obj_t pin_P0_15;
+extern const mcu_pin_obj_t pin_P0_16;
+extern const mcu_pin_obj_t pin_P0_17;
+extern const mcu_pin_obj_t pin_P0_18;
+extern const mcu_pin_obj_t pin_P0_19;
+extern const mcu_pin_obj_t pin_P0_20;
+extern const mcu_pin_obj_t pin_P0_21;
+extern const mcu_pin_obj_t pin_P0_22;
+extern const mcu_pin_obj_t pin_P0_23;
+extern const mcu_pin_obj_t pin_P0_24;
+extern const mcu_pin_obj_t pin_P0_25;
+extern const mcu_pin_obj_t pin_P0_26;
+extern const mcu_pin_obj_t pin_P0_27;
+extern const mcu_pin_obj_t pin_P0_28;
+extern const mcu_pin_obj_t pin_P0_29;
+extern const mcu_pin_obj_t pin_P0_30;
+extern const mcu_pin_obj_t pin_P0_31;
+extern const mcu_pin_obj_t pin_P1_00;
+extern const mcu_pin_obj_t pin_P1_01;
+extern const mcu_pin_obj_t pin_P1_02;
+extern const mcu_pin_obj_t pin_P1_03;
+extern const mcu_pin_obj_t pin_P1_04;
+extern const mcu_pin_obj_t pin_P1_05;
+extern const mcu_pin_obj_t pin_P1_06;
+extern const mcu_pin_obj_t pin_P1_07;
+extern const mcu_pin_obj_t pin_P1_08;
+extern const mcu_pin_obj_t pin_P1_09;
+
+#endif // MICROPY_INCLUDED_NRF_PERIPHERALS_NRF52833_PINS_H
diff --git a/ports/nrf/peripherals/nrf/nrf52833/power.c b/ports/nrf/peripherals/nrf/nrf52833/power.c
new file mode 100644
index 000000000..d64c536bb
--- /dev/null
+++ b/ports/nrf/peripherals/nrf/nrf52833/power.c
@@ -0,0 +1,50 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Dan Halbert 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 "nrfx.h"
+#include "hal/nrf_nvmc.h"
+
+void nrf_peripherals_power_init(void) {
+    // Set GPIO reference voltage to 3.3V if it isn't already. REGOUT0 will get reset to 0xfffffff
+    // if flash is erased, which sets the default to 1.8V
+    // This matters only when "high voltage mode" is enabled, which is true on the PCA10059,
+    // and might be true on other boards.
+    if (NRF_UICR->REGOUT0 == 0xffffffff && NRF_POWER->MAINREGSTATUS & 1) {
+        // Expand what nrf_nvmc_word_write() did.
+        // It's missing from nrfx V2.0.0, and nrfx_nvmc_word_write() does bounds
+        // checking which prevents writes to UICR.
+        // Reported: https://devzone.nordicsemi.com/f/nordic-q-a/57243/nrfx_nvmc-h-api-cannot-write-to-uicr
+        NRF_NVMC->CONFIG = NRF_NVMC_MODE_WRITE;
+        while (!(NRF_NVMC->READY & NVMC_READY_READY_Msk)) {}
+        NRF_UICR->REGOUT0 = UICR_REGOUT0_VOUT_3V3 << UICR_REGOUT0_VOUT_Pos;
+        __DMB();
+        while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {}
+        NRF_NVMC->CONFIG = NRF_NVMC_MODE_READONLY;
+
+        // Must reset to enable change.
+        NVIC_SystemReset();
+    }
+}
diff --git a/ports/nrf/peripherals/nrf/pins.h b/ports/nrf/peripherals/nrf/pins.h
index 3a4c99579..efdc8892a 100644
--- a/ports/nrf/peripherals/nrf/pins.h
+++ b/ports/nrf/peripherals/nrf/pins.h
@@ -61,4 +61,9 @@ extern const mp_obj_type_t mcu_pin_type;
 #include "nrf52840/pins.h"
 #endif
 
+// Choose based on chip, but not specifically revision (e.g., not NRF52840_XXAA)
+#ifdef NRF52833
+#include "nrf52833/pins.h"
+#endif
+
 #endif // __MICROPY_INCLUDED_NRF_PERIPHERALS_PINS_H__