diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 86143c8efb..c393afe7d8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -75,6 +75,7 @@ jobs:
         board:
         - "arduino_mkr1300"
         - "arduino_mkrzero"
+        - "arduino_nano_33_ble"
         - "arduino_zero"
         - "bast_pro_mini_m0"
         - "capablerobot_usbhub"
@@ -109,6 +110,7 @@ jobs:
         - "hallowing_m4_express"
         - "itsybitsy_m0_express"
         - "itsybitsy_m4_express"
+        - "itsybitsy_nrf52840_express"
         - "kicksat-sprite"
         - "makerdiary_nrf52840_mdk"
         - "makerdiary_nrf52840_mdk_usb_dongle"
diff --git a/locale/de_DE.po b/locale/de_DE.po
index b790e86bdf..971687d19f 100644
--- a/locale/de_DE.po
+++ b/locale/de_DE.po
@@ -737,7 +737,7 @@ msgstr ""
 
 #: ports/atmel-samd/common-hal/frequencyio/FrequencyIn.c
 msgid "Frequency captured is above capability. Capture Paused."
-msgstr ""
+msgstr "Die aufgezeichnete Frequenz liegt über der Leistungsgrenze. Aufnahme angehalten."
 
 #: shared-bindings/bitbangio/I2C.c shared-bindings/bitbangio/SPI.c
 #: shared-bindings/busio/I2C.c shared-bindings/busio/SPI.c
diff --git a/ports/atmel-samd/boards/pyportal_titano/board.c b/ports/atmel-samd/boards/pyportal_titano/board.c
index a18bb380bb..828ceebc4e 100644
--- a/ports/atmel-samd/boards/pyportal_titano/board.c
+++ b/ports/atmel-samd/boards/pyportal_titano/board.c
@@ -74,24 +74,21 @@ uint8_t display_init_sequence[] = {
       0x11, 0x1d, 0x23, 0x35, 0x41, 0x4b, 0x4b, 0x42, 0x3A,
       0x27, 0x1B, 0x08, 0x09, 0x03, 0x00, 0x01,
     0x3a, 1, 0x55,
-    0x36, 1, 0x00,
+    0x36, 1, 0x60,
     0x11, DELAY, 150/5, // Exit Sleep, then delay 150 ms
     0x29, DELAY, 50/5
 };
 
 void board_init(void) {
-    busio_spi_obj_t* spi = &displays[0].fourwire_bus.inline_bus;
-    common_hal_busio_spi_construct(spi, &pin_PA13, &pin_PA12, &pin_PA14);
-    common_hal_busio_spi_never_reset(spi);
-    
-    displayio_fourwire_obj_t* bus = &displays[0].fourwire_bus;
-    bus->base.type = &displayio_fourwire_type;
-    common_hal_displayio_fourwire_construct(bus,
-        spi,
-        &pin_PB05, // TFT_DC Command or data
-        &pin_PB06, // TFT_CS Chip select
-        &pin_PA00, // TFT_RST Reset
-        24000000);
+    displayio_parallelbus_obj_t* bus = &displays[0].parallel_bus;
+    bus->base.type = &displayio_parallelbus_type;
+    common_hal_displayio_parallelbus_construct(bus,
+        &pin_PA16, // Data0
+        &pin_PB05, // Command or data
+        &pin_PB06, // Chip select
+        &pin_PB09, // Write
+        &pin_PB04, // Read
+        &pin_PA00); // Reset
 
     displayio_display_obj_t* display = &displays[0].display;
     display->base.type = &displayio_display_type;
@@ -101,7 +98,7 @@ void board_init(void) {
         320, // Height
         0, // column start
         0, // row start
-        270, // rotation
+        0, // rotation
         16, // Color depth
         false, // grayscale
         false, // pixels_in_byte_share_row (unused for depths > 8)
diff --git a/ports/atmel-samd/boards/pyportal_titano/mpconfigboard.h b/ports/atmel-samd/boards/pyportal_titano/mpconfigboard.h
index 91c1188108..f2af07371c 100644
--- a/ports/atmel-samd/boards/pyportal_titano/mpconfigboard.h
+++ b/ports/atmel-samd/boards/pyportal_titano/mpconfigboard.h
@@ -3,7 +3,6 @@
 
 #define CIRCUITPY_MCU_FAMILY samd51
 
-
 #define MICROPY_HW_LED_STATUS   (&pin_PA27)
 
 #define MICROPY_HW_NEOPIXEL (&pin_PB22)
diff --git a/ports/atmel-samd/boards/pyportal_titano/pins.c b/ports/atmel-samd/boards/pyportal_titano/pins.c
index 6bc0a504a4..14699a209d 100644
--- a/ports/atmel-samd/boards/pyportal_titano/pins.c
+++ b/ports/atmel-samd/boards/pyportal_titano/pins.c
@@ -80,15 +80,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
     { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 
-    // TFT control pins
-    {MP_OBJ_NEW_QSTR(MP_QSTR_TFT_LITE), MP_ROM_PTR(&pin_PB31)},
-    {MP_OBJ_NEW_QSTR(MP_QSTR_TFT_MOSI), MP_ROM_PTR(&pin_PA12)},
-    {MP_OBJ_NEW_QSTR(MP_QSTR_TFT_SCK), MP_ROM_PTR(&pin_PA13)},
-    {MP_OBJ_NEW_QSTR(MP_QSTR_TFT_MISO), MP_ROM_PTR(&pin_PA14)},
-    {MP_OBJ_NEW_QSTR(MP_QSTR_TFT_RST), MP_ROM_PTR(&pin_PA00)},
-    {MP_ROM_QSTR(MP_QSTR_TFT_CS), MP_ROM_PTR(&pin_PB06)},
-    {MP_ROM_QSTR(MP_QSTR_TFT_DC), MP_ROM_PTR(&pin_PB05)},
-
     { MP_ROM_QSTR(MP_QSTR_DISPLAY), MP_ROM_PTR(&displays[0].display) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/common-hal/busio/I2C.c b/ports/atmel-samd/common-hal/busio/I2C.c
index cdc616bbc8..b0e5714a79 100644
--- a/ports/atmel-samd/common-hal/busio/I2C.c
+++ b/ports/atmel-samd/common-hal/busio/I2C.c
@@ -116,6 +116,7 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     if (i2c_m_sync_set_baudrate(&self->i2c_desc, 0, frequency / 1000) != ERR_NONE) {
         reset_pin_number(sda->number);
         reset_pin_number(scl->number);
+        common_hal_busio_i2c_deinit(self);
         mp_raise_ValueError(translate("Unsupported baudrate"));
     }
 
diff --git a/ports/atmel-samd/common-hal/pulseio/PWMOut.c b/ports/atmel-samd/common-hal/pulseio/PWMOut.c
index 6dcace21fd..0adb23fc5d 100644
--- a/ports/atmel-samd/common-hal/pulseio/PWMOut.c
+++ b/ports/atmel-samd/common-hal/pulseio/PWMOut.c
@@ -135,6 +135,7 @@ pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
                                                     bool variable_frequency) {
     self->pin = pin;
     self->variable_frequency = variable_frequency;
+    self->duty_cycle = duty;
 
     if (pin->timer[0].index >= TC_INST_NUM &&
         pin->timer[1].index >= TCC_INST_NUM
@@ -322,6 +323,13 @@ void common_hal_pulseio_pwmout_deinit(pulseio_pwmout_obj_t* self) {
 }
 
 extern void common_hal_pulseio_pwmout_set_duty_cycle(pulseio_pwmout_obj_t* self, uint16_t duty) {
+    // Store the unadjusted duty cycle. It turns out the the process of adjusting and calculating
+    // the duty cycle here and reading it back is lossy - the value will decay over time.
+    // Track it here so that if frequency is changed we can use this value to recalculate the
+    // proper duty cycle.
+    // See https://github.com/adafruit/circuitpython/issues/2086 for more details
+    self->duty_cycle = duty;
+
     const pin_timer_t* t = self->timer;
     if (t->is_tc) {
         uint16_t adjusted_duty = tc_periods[t->index] * duty / 0xffff;
@@ -415,7 +423,6 @@ void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self,
             break;
         }
     }
-    uint16_t old_duty = common_hal_pulseio_pwmout_get_duty_cycle(self);
     if (t->is_tc) {
         Tc* tc = tc_insts[t->index];
         uint8_t old_divisor = tc->COUNT16.CTRLA.bit.PRESCALER;
@@ -450,7 +457,7 @@ void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self,
         #endif
     }
 
-    common_hal_pulseio_pwmout_set_duty_cycle(self, old_duty);
+    common_hal_pulseio_pwmout_set_duty_cycle(self, self->duty_cycle);
 }
 
 uint32_t common_hal_pulseio_pwmout_get_frequency(pulseio_pwmout_obj_t* self) {
diff --git a/ports/atmel-samd/common-hal/pulseio/PWMOut.h b/ports/atmel-samd/common-hal/pulseio/PWMOut.h
index eef653bcb2..09abda8196 100644
--- a/ports/atmel-samd/common-hal/pulseio/PWMOut.h
+++ b/ports/atmel-samd/common-hal/pulseio/PWMOut.h
@@ -36,6 +36,7 @@ typedef struct {
     const mcu_pin_obj_t *pin;
     const pin_timer_t* timer;
     bool variable_frequency;
+    uint16_t duty_cycle;
 } pulseio_pwmout_obj_t;
 
 void pwmout_reset(void);
diff --git a/ports/cxd56/boards/spresense/mpconfigboard.h b/ports/cxd56/boards/spresense/mpconfigboard.h
index b20d006586..0245e20450 100644
--- a/ports/cxd56/boards/spresense/mpconfigboard.h
+++ b/ports/cxd56/boards/spresense/mpconfigboard.h
@@ -26,7 +26,6 @@
 
 #define MICROPY_HW_BOARD_NAME "SPRESENSE"
 #define MICROPY_HW_MCU_NAME "CXD5602"
-#define MICROPY_PY_SYS_PLATFORM "SPRESENSE"
 
 #define DEFAULT_I2C_BUS_SCL (&pin_I2C0_BCK)
 #define DEFAULT_I2C_BUS_SDA (&pin_I2C0_BDT)
diff --git a/ports/cxd56/mpconfigport.h b/ports/cxd56/mpconfigport.h
index 91ebfd98f6..df87946b95 100644
--- a/ports/cxd56/mpconfigport.h
+++ b/ports/cxd56/mpconfigport.h
@@ -27,6 +27,8 @@
 #ifndef __INCLUDED_MPCONFIGPORT_H
 #define __INCLUDED_MPCONFIGPORT_H
 
+#define MICROPY_PY_SYS_PLATFORM "CXD56"
+
 // 64kiB stack
 #define CIRCUITPY_DEFAULT_STACK_SIZE            0x10000
 
diff --git a/ports/nrf/boards/arduino_nano_33_ble/README.md b/ports/nrf/boards/arduino_nano_33_ble/README.md
new file mode 100644
index 0000000000..42d7a86184
--- /dev/null
+++ b/ports/nrf/boards/arduino_nano_33_ble/README.md
@@ -0,0 +1,27 @@
+# Arduino Nano 33 BLE and Nano 33 BLE Sense
+
+The [Arduino Nano 33 BLE](https://store.arduino.cc/usa/nano-33-ble-with-headers) and
+[Arduino Nano 33 BLE Sense](https://store.arduino.cc/usa/nano-33-ble-sense) and
+are built around the NINA B306 module, based on Nordic nRF 52840 and containing
+a powerful Cortex M4F. Both include an onboard 9 axis Inertial Measurement Unit (IMU), the LSM9DS1.
+The Nano 33 BLE Sense adds an LPS22HB barometric pressure and temperature sensor,
+an ADPS-9960 digital proximity, ambient light, RGB, and gensture sensor,
+and an MP34DT05 digital microphone.
+
+Note: the Arduino Nano 33 BLE and BLE Sense do not include a QSPI external
+flash. Any Python code will need to be stored on the internal flash
+filesystem.
+
+I2C pins `board.SCL1` and `board.SDA1` are not exposed and are used for onboard peripherals.
+Pin `board.R_PULLUP` must be set to high to enable the `SCL1` and `SDA1` pullups for proper operation.
+
+Pin `board.VDD_ENV` applies power to the LSM9DS1, and must be high for it to be operational.
+
+Pins `board.MIC_PWR`, `board.PDMDIN`, and `board.PDMCLK` are for the Nano 33 BLE Sense onboard microphone.
+
+Pin `board.INT_ADPS` is the interrupt pin from the ADPS-9960.
+
+Pins `board.RGB_LED_R`, `board.RGB_LED_G`, and `board.RGB_LED_B`
+are the red, green and blue LEDS in the onboard RGB LED.
+
+Pins `board.LED_G` and `board.LED_Y` are onboard green and red LEDs. `board.LED_Y` is also `board.SCK`.
diff --git a/ports/nrf/boards/arduino_nano_33_ble/board.c b/ports/nrf/boards/arduino_nano_33_ble/board.c
new file mode 100644
index 0000000000..ddfcde2848
--- /dev/null
+++ b/ports/nrf/boards/arduino_nano_33_ble/board.c
@@ -0,0 +1,63 @@
+/*
+ * 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 "boards/board.h"
+#include "nrf.h"
+#include "nrf_rtc.h"
+
+void board_init(void) {
+    // Initializations below from Arduino variant.cpp.
+
+    // // turn power LED on
+    // pinMode(LED_PWR, OUTPUT);
+    // digitalWrite(LED_PWR, HIGH);
+
+    // Errata Nano33BLE - I2C pullup is on SWO line, need to disable TRACE
+    // was being enabled by nrfx_clock_anomaly_132
+    CoreDebug->DEMCR = 0;
+    NRF_CLOCK->TRACECONFIG = 0;
+
+    // FIXME: bootloader enables interrupt on COMPARE[0], which we don't handle
+    // Disable it here to avoid getting stuck when OVERFLOW irq is triggered
+    nrf_rtc_event_disable(NRF_RTC1, NRF_RTC_INT_COMPARE0_MASK);
+    nrf_rtc_int_disable(NRF_RTC1, NRF_RTC_INT_COMPARE0_MASK);
+
+    // // FIXME: always enable I2C pullup and power @startup
+    // // Change for maximum powersave
+    // pinMode(PIN_ENABLE_SENSORS_3V3, OUTPUT);
+    // pinMode(PIN_ENABLE_I2C_PULLUP, OUTPUT);
+
+    // digitalWrite(PIN_ENABLE_SENSORS_3V3, HIGH);
+    // digitalWrite(PIN_ENABLE_I2C_PULLUP, HIGH);
+}
+
+bool board_requests_safe_mode(void) {
+  return false;
+}
+
+void reset_board(void) {
+
+}
diff --git a/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.h b/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.h
new file mode 100644
index 0000000000..d34a862439
--- /dev/null
+++ b/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.h
@@ -0,0 +1,16 @@
+#include "nrfx/hal/nrf_gpio.h"
+
+#define MICROPY_HW_BOARD_NAME       "Arduino Nano 33 BLE"
+#define MICROPY_HW_MCU_NAME         "nRF52840"
+
+#define CIRCUITPY_AUTORELOAD_DELAY_MS 500
+
+#define DEFAULT_I2C_BUS_SCL         (&pin_P0_02)
+#define DEFAULT_I2C_BUS_SDA         (&pin_P0_31)
+
+#define DEFAULT_SPI_BUS_SCK         (&pin_P0_13)
+#define DEFAULT_SPI_BUS_MOSI        (&pin_P0_01)
+#define DEFAULT_SPI_BUS_MISO        (&pin_P1_08)
+
+#define DEFAULT_UART_BUS_RX         (&pin_P1_10)
+#define DEFAULT_UART_BUS_TX         (&pin_P1_03)
diff --git a/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.mk b/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.mk
new file mode 100644
index 0000000000..9a875ac442
--- /dev/null
+++ b/ports/nrf/boards/arduino_nano_33_ble/mpconfigboard.mk
@@ -0,0 +1,31 @@
+USB_VID = 0x2341
+USB_PID = 0x805A
+USB_PRODUCT = "Arduino_Nano_33_BLE"
+USB_MANUFACTURER = "Arduino"
+
+MCU_SERIES = m4
+MCU_VARIANT = nrf52
+MCU_SUB_VARIANT = nrf52840
+MCU_CHIP = nrf52840
+SD ?= s140
+SOFTDEV_VERSION ?= 6.1.0
+
+BOOT_SETTING_ADDR = 0xFF000
+
+ifeq ($(SD),)
+	LD_FILE = boards/nrf52840_1M_256k.ld
+else
+	LD_FILE = boards/adafruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_v$(firstword $(subst ., ,$(SOFTDEV_VERSION))).ld
+	CIRCUITPY_BLEIO = 1
+endif
+
+NRF_DEFINES += -DNRF52840_XXAA -DNRF52840
+
+INTERNAL_FLASH_FILESYSTEM = 1
+
+# Allocate two, not just one I2C peripheral, so that we have both
+# on-board and off-board I2C available.
+# When SPIM3 becomes available we'll be able to have two I2C and two SPI peripherals.
+# We use a CFLAGS define here because there are include order issues
+# if we try to include "mpconfigport.h" into nrfx_config.h .
+CFLAGS += -DCIRCUITPY_NRF_NUM_I2C=2
diff --git a/ports/nrf/boards/arduino_nano_33_ble/pins.c b/ports/nrf/boards/arduino_nano_33_ble/pins.c
new file mode 100644
index 0000000000..9cdd369331
--- /dev/null
+++ b/ports/nrf/boards/arduino_nano_33_ble/pins.c
@@ -0,0 +1,63 @@
+#include "shared-bindings/board/__init__.h"
+
+STATIC const mp_rom_map_elem_t board_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_D2), MP_ROM_PTR(&pin_P1_11) },
+    { MP_ROM_QSTR(MP_QSTR_D3), MP_ROM_PTR(&pin_P1_12) },
+    { MP_ROM_QSTR(MP_QSTR_D4), MP_ROM_PTR(&pin_P1_15) },
+    { MP_ROM_QSTR(MP_QSTR_D5), MP_ROM_PTR(&pin_P1_13) },
+    { MP_ROM_QSTR(MP_QSTR_D6), MP_ROM_PTR(&pin_P1_14) },
+    { MP_ROM_QSTR(MP_QSTR_D7), MP_ROM_PTR(&pin_P0_23) },
+    { MP_ROM_QSTR(MP_QSTR_D8), MP_ROM_PTR(&pin_P0_21) },
+    { MP_ROM_QSTR(MP_QSTR_D9), MP_ROM_PTR(&pin_P0_27) },
+    { MP_ROM_QSTR(MP_QSTR_D10), MP_ROM_PTR(&pin_P1_02) },
+
+    { MP_ROM_QSTR(MP_QSTR_A0), MP_ROM_PTR(&pin_P0_04) },
+    { MP_ROM_QSTR(MP_QSTR_A1), MP_ROM_PTR(&pin_P0_05) },
+    { MP_ROM_QSTR(MP_QSTR_A2), MP_ROM_PTR(&pin_P0_30) },
+    { MP_ROM_QSTR(MP_QSTR_A3), MP_ROM_PTR(&pin_P0_29) },
+
+    { MP_ROM_QSTR(MP_QSTR_A4), MP_ROM_PTR(&pin_P0_31) },
+    { MP_ROM_QSTR(MP_QSTR_SDA), MP_ROM_PTR(&pin_P0_31) },
+
+    { MP_ROM_QSTR(MP_QSTR_A5), MP_ROM_PTR(&pin_P0_02) },
+    { MP_ROM_QSTR(MP_QSTR_SCL), MP_ROM_PTR(&pin_P0_02) },
+
+    { MP_ROM_QSTR(MP_QSTR_A6), MP_ROM_PTR(&pin_P0_28) },
+    { MP_ROM_QSTR(MP_QSTR_A7), MP_ROM_PTR(&pin_P0_03) },
+
+    { MP_ROM_QSTR(MP_QSTR_SDA1), MP_ROM_PTR(&pin_P0_14) },
+    { MP_ROM_QSTR(MP_QSTR_SCL1), MP_ROM_PTR(&pin_P0_15) },
+
+    { MP_ROM_QSTR(MP_QSTR_MOSI), MP_ROM_PTR(&pin_P1_01) },
+    { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_P1_08) },
+
+    { MP_ROM_QSTR(MP_QSTR_SCK), MP_ROM_PTR(&pin_P0_13) },
+    { MP_ROM_QSTR(MP_QSTR_LED_Y), MP_ROM_PTR(&pin_P0_13)  },
+
+    { MP_ROM_QSTR(MP_QSTR_LED_G), MP_ROM_PTR(&pin_P1_09)  },
+
+    { MP_ROM_QSTR(MP_QSTR_RGB_LED_R), MP_ROM_PTR(&pin_P0_24)  },
+    { MP_ROM_QSTR(MP_QSTR_RGB_LED_G), MP_ROM_PTR(&pin_P0_16)  },
+    { MP_ROM_QSTR(MP_QSTR_RGB_LED_B), MP_ROM_PTR(&pin_P0_06)  },
+
+    // Power line to LSM9DS1.
+    { MP_ROM_QSTR(MP_QSTR_VDD_ENV), MP_ROM_PTR(&pin_P0_22)  },
+
+    // Pullup voltage for SDA1 and SCL1
+    { MP_ROM_QSTR(MP_QSTR_R_PULLUP), MP_ROM_PTR(&pin_P1_00)  },
+
+    { MP_ROM_QSTR(MP_QSTR_MIC_PWR), MP_ROM_PTR(&pin_P0_17)  },
+    { MP_ROM_QSTR(MP_QSTR_PDMCLK), MP_ROM_PTR(&pin_P0_26)  },
+    { MP_ROM_QSTR(MP_QSTR_PDMDIN), MP_ROM_PTR(&pin_P0_25)  },
+
+    { MP_ROM_QSTR(MP_QSTR_INT_APDS), MP_ROM_PTR(&pin_P0_19)  },
+
+    { MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_PTR(&pin_P1_03) },
+    { MP_ROM_QSTR(MP_QSTR_RX), MP_ROM_PTR(&pin_P1_10) },
+
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
+    { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
+};
+
+MP_DEFINE_CONST_DICT(board_module_globals, board_module_globals_table);
diff --git a/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.h b/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.h
index 1e55cd0260..4e37eae0aa 100644
--- a/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.h
+++ b/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Adafruit Circuit Playground Bluefruit"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "CircuitPlaygroundBluefruit"
 
 #define FLASH_SIZE                  (0x100000)
 #define FLASH_PAGE_SIZE             (4096)
@@ -70,3 +69,5 @@
 
 #define DEFAULT_UART_BUS_RX         (&pin_P0_30)
 #define DEFAULT_UART_BUS_TX         (&pin_P0_14)
+
+#define SPEAKER_ENABLE_PIN          (&pin_P1_04)
diff --git a/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.mk b/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.mk
index dbb32629c6..d53e486f9d 100644
--- a/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.mk
+++ b/ports/nrf/boards/circuitplayground_bluefruit/mpconfigboard.mk
@@ -24,3 +24,10 @@ NRF_DEFINES += -DNRF52840_XXAA -DNRF52840
 QSPI_FLASH_FILESYSTEM = 1
 EXTERNAL_FLASH_DEVICE_COUNT = 1
 EXTERNAL_FLASH_DEVICES = "GD25Q16C"
+
+# Allocate two, not just one I2C peripheral for CPB, so that we have both
+# on-board and off-board I2C available.
+# When SPIM3 becomes available we'll be able to have two I2C and two SPI peripherals.
+# We use a CFLAGS define here because there are include order issues
+# if we try to include "mpconfigport.h" into nrfx_config.h .
+CFLAGS += -DCIRCUITPY_NRF_NUM_I2C=2
diff --git a/ports/nrf/boards/electronut_labs_blip/mpconfigboard.h b/ports/nrf/boards/electronut_labs_blip/mpconfigboard.h
index 21e8c3ef61..6fe969d4ac 100644
--- a/ports/nrf/boards/electronut_labs_blip/mpconfigboard.h
+++ b/ports/nrf/boards/electronut_labs_blip/mpconfigboard.h
@@ -32,7 +32,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Electronut Labs Blip"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "ElectronutLabsPapyr"
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
diff --git a/ports/nrf/boards/electronut_labs_papyr/mpconfigboard.h b/ports/nrf/boards/electronut_labs_papyr/mpconfigboard.h
index 7f5021fdca..6fc1c5fad7 100644
--- a/ports/nrf/boards/electronut_labs_papyr/mpconfigboard.h
+++ b/ports/nrf/boards/electronut_labs_papyr/mpconfigboard.h
@@ -31,7 +31,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Electronut Labs Papyr"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "ElectronutLabsPapyr"
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
diff --git a/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h b/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
index 70ccffc3f3..b5319032c9 100644
--- a/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
+++ b/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Adafruit Feather nRF52840 Express"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "Feather52840Express"
 
 #define FLASH_SIZE                  (0x100000)
 #define FLASH_PAGE_SIZE             (4096)
diff --git a/ports/nrf/boards/itsybitsy_nrf52840_express/board.c b/ports/nrf/boards/itsybitsy_nrf52840_express/board.c
new file mode 100644
index 0000000000..4421970eef
--- /dev/null
+++ b/ports/nrf/boards/itsybitsy_nrf52840_express/board.c
@@ -0,0 +1,38 @@
+/*
+ * 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 "boards/board.h"
+
+void board_init(void) {
+}
+
+bool board_requests_safe_mode(void) {
+  return false;
+}
+
+void reset_board(void) {
+
+}
diff --git a/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.h b/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.h
new file mode 100644
index 0000000000..2f17460ae7
--- /dev/null
+++ b/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.h
@@ -0,0 +1,46 @@
+#include "nrfx/hal/nrf_gpio.h"
+
+#define MICROPY_HW_BOARD_NAME       "Adafruit ItsyBitsy nRF52840 Express"
+#define MICROPY_HW_MCU_NAME         "nRF52840"
+
+#define FLASH_SIZE                  (0x100000)
+#define FLASH_PAGE_SIZE             (4096)
+
+#define MICROPY_HW_LED_STATUS       (&pin_P0_06)
+
+#define MICROPY_HW_APA102_MOSI   (&pin_P0_08)
+#define MICROPY_HW_APA102_SCK    (&pin_P1_09)
+
+#if QSPI_FLASH_FILESYSTEM
+#define MICROPY_QSPI_DATA0                NRF_GPIO_PIN_MAP(0, 21)
+#define MICROPY_QSPI_DATA1                NRF_GPIO_PIN_MAP(0, 22)
+#define MICROPY_QSPI_DATA2                NRF_GPIO_PIN_MAP(1, 00)
+#define MICROPY_QSPI_DATA3                NRF_GPIO_PIN_MAP(0, 17)
+#define MICROPY_QSPI_SCK                  NRF_GPIO_PIN_MAP(0, 19)
+#define MICROPY_QSPI_CS                   NRF_GPIO_PIN_MAP(0, 23)
+#endif
+
+#if SPI_FLASH_FILESYSTEM
+#define SPI_FLASH_MOSI_PIN &pin_P0_21
+#define SPI_FLASH_MISO_PIN &pin_P0_22
+#define SPI_FLASH_SCK_PIN &pin_P0_19
+#define SPI_FLASH_CS_PIN &pin_P0_23
+#endif
+
+#define CIRCUITPY_AUTORELOAD_DELAY_MS 500
+
+#define CIRCUITPY_INTERNAL_NVM_SIZE (4096)
+
+#define BOARD_FLASH_SIZE (FLASH_SIZE - 0x4000 - CIRCUITPY_INTERNAL_NVM_SIZE)
+
+#define BOARD_HAS_CRYSTAL 1
+
+#define DEFAULT_I2C_BUS_SCL         (&pin_P0_14)
+#define DEFAULT_I2C_BUS_SDA         (&pin_P0_16)
+
+#define DEFAULT_SPI_BUS_SCK         (&pin_P0_13)
+#define DEFAULT_SPI_BUS_MOSI        (&pin_P0_15)
+#define DEFAULT_SPI_BUS_MISO        (&pin_P0_20)
+
+#define DEFAULT_UART_BUS_RX         (&pin_P0_25)
+#define DEFAULT_UART_BUS_TX         (&pin_P0_24)
diff --git a/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.mk b/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.mk
new file mode 100644
index 0000000000..d290077e75
--- /dev/null
+++ b/ports/nrf/boards/itsybitsy_nrf52840_express/mpconfigboard.mk
@@ -0,0 +1,29 @@
+USB_VID = 0x239A
+USB_PID = 0x8052
+USB_PRODUCT = "ItsyBitsy nRF52840 Express"
+USB_MANUFACTURER = "Adafruit Industries LLC"
+
+MCU_SERIES = m4
+MCU_VARIANT = nrf52
+MCU_SUB_VARIANT = nrf52840
+MCU_CHIP = nrf52840
+SD ?= s140
+SOFTDEV_VERSION ?= 6.1.0
+
+BOOT_SETTING_ADDR = 0xFF000
+
+ifeq ($(SD),)
+	LD_FILE = boards/nrf52840_1M_256k.ld
+else
+	LD_FILE = boards/adafruit_$(MCU_SUB_VARIANT)_$(SD_LOWER)_v$(firstword $(subst ., ,$(SOFTDEV_VERSION))).ld
+	CIRCUITPY_BLEIO = 1
+endif
+
+NRF_DEFINES += -DNRF52840_XXAA -DNRF52840
+
+# Don't use up a hardware SPI peripheral for the status DotStar: we only have one or two.
+CIRCUITPY_BITBANG_APA102 = 1
+
+QSPI_FLASH_FILESYSTEM = 1
+EXTERNAL_FLASH_DEVICE_COUNT = 1
+EXTERNAL_FLASH_DEVICES = "GD25Q16C"
diff --git a/ports/nrf/boards/itsybitsy_nrf52840_express/pins.c b/ports/nrf/boards/itsybitsy_nrf52840_express/pins.c
new file mode 100644
index 0000000000..364fbfd470
--- /dev/null
+++ b/ports/nrf/boards/itsybitsy_nrf52840_express/pins.c
@@ -0,0 +1,46 @@
+#include "shared-bindings/board/__init__.h"
+
+STATIC const mp_rom_map_elem_t board_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_A0), MP_ROM_PTR(&pin_P0_04) },
+    { MP_ROM_QSTR(MP_QSTR_A1), MP_ROM_PTR(&pin_P0_30) },
+    { MP_ROM_QSTR(MP_QSTR_A2), MP_ROM_PTR(&pin_P0_28) },
+    { MP_ROM_QSTR(MP_QSTR_A3), MP_ROM_PTR(&pin_P0_31) },
+    { MP_ROM_QSTR(MP_QSTR_A4), MP_ROM_PTR(&pin_P0_02) },
+    { MP_ROM_QSTR(MP_QSTR_A5), MP_ROM_PTR(&pin_P0_03) },
+
+    { MP_ROM_QSTR(MP_QSTR_SWITCH), MP_ROM_PTR(&pin_P0_29) },
+
+    { MP_ROM_QSTR(MP_QSTR_D0), MP_ROM_PTR(&pin_P0_25) },
+    { MP_ROM_QSTR(MP_QSTR_RX), MP_ROM_PTR(&pin_P0_25) },
+
+    { MP_ROM_QSTR(MP_QSTR_D1), MP_ROM_PTR(&pin_P0_24) },
+    { MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_PTR(&pin_P0_24) },
+
+    { MP_ROM_QSTR(MP_QSTR_D2), MP_ROM_PTR(&pin_P1_02) },
+    { MP_ROM_QSTR(MP_QSTR_D5), MP_ROM_PTR(&pin_P0_27) },
+    { MP_ROM_QSTR(MP_QSTR_D7), MP_ROM_PTR(&pin_P1_08) },
+    { MP_ROM_QSTR(MP_QSTR_D9), MP_ROM_PTR(&pin_P0_07) },
+    { MP_ROM_QSTR(MP_QSTR_D10), MP_ROM_PTR(&pin_P0_05) },
+    { MP_ROM_QSTR(MP_QSTR_D11), MP_ROM_PTR(&pin_P0_26) },
+    { MP_ROM_QSTR(MP_QSTR_D12), MP_ROM_PTR(&pin_P0_11) },
+    { MP_ROM_QSTR(MP_QSTR_D13), MP_ROM_PTR(&pin_P0_12) },
+
+    { MP_ROM_QSTR(MP_QSTR_SCL), MP_ROM_PTR(&pin_P0_14) },
+    { MP_ROM_QSTR(MP_QSTR_SDA), MP_ROM_PTR(&pin_P0_16) },
+
+    { MP_ROM_QSTR(MP_QSTR_APA102_MOSI), MP_ROM_PTR(&pin_P0_08) },
+    { MP_ROM_QSTR(MP_QSTR_APA102_SCK), MP_ROM_PTR(&pin_P1_09) },
+
+    { MP_ROM_QSTR(MP_QSTR_SCK), MP_ROM_PTR(&pin_P0_13) },
+    { MP_ROM_QSTR(MP_QSTR_MOSI), MP_ROM_PTR(&pin_P0_15) },
+    { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_P0_20) },
+
+    { MP_ROM_QSTR(MP_QSTR_L), MP_ROM_PTR(&pin_P0_06) },
+    { MP_ROM_QSTR(MP_QSTR_BLUE_LED), MP_ROM_PTR(&pin_P0_06) },
+
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
+    { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
+};
+
+MP_DEFINE_CONST_DICT(board_module_globals, board_module_globals_table);
diff --git a/ports/nrf/boards/makerdiary_nrf52840_mdk/mpconfigboard.h b/ports/nrf/boards/makerdiary_nrf52840_mdk/mpconfigboard.h
index ed48364942..ce0abe724e 100644
--- a/ports/nrf/boards/makerdiary_nrf52840_mdk/mpconfigboard.h
+++ b/ports/nrf/boards/makerdiary_nrf52840_mdk/mpconfigboard.h
@@ -31,7 +31,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "MakerDiary nRF52840 MDK"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "MakerDiary52840MDK"
 
 #define MICROPY_QSPI_DATA0                NRF_GPIO_PIN_MAP(1, 5)
 #define MICROPY_QSPI_DATA1                NRF_GPIO_PIN_MAP(1, 4)
diff --git a/ports/nrf/boards/makerdiary_nrf52840_mdk_usb_dongle/mpconfigboard.h b/ports/nrf/boards/makerdiary_nrf52840_mdk_usb_dongle/mpconfigboard.h
index d4096503d7..86c7243e57 100644
--- a/ports/nrf/boards/makerdiary_nrf52840_mdk_usb_dongle/mpconfigboard.h
+++ b/ports/nrf/boards/makerdiary_nrf52840_mdk_usb_dongle/mpconfigboard.h
@@ -31,7 +31,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "MakerDiary nRF52840 MDK USB Dongle"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "MakerDiary52840MDKDongle"
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
diff --git a/ports/nrf/boards/metro_nrf52840_express/mpconfigboard.h b/ports/nrf/boards/metro_nrf52840_express/mpconfigboard.h
index 520eef90d9..797cc9668c 100644
--- a/ports/nrf/boards/metro_nrf52840_express/mpconfigboard.h
+++ b/ports/nrf/boards/metro_nrf52840_express/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Adafruit Metro nRF52840 Express"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "Metro52840Express"
 
 #define FLASH_SIZE                  (0x100000)
 #define FLASH_PAGE_SIZE             (4096)
diff --git a/ports/nrf/boards/particle_argon/mpconfigboard.h b/ports/nrf/boards/particle_argon/mpconfigboard.h
index a4ecb2bb43..1eeb7291bc 100644
--- a/ports/nrf/boards/particle_argon/mpconfigboard.h
+++ b/ports/nrf/boards/particle_argon/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Particle Argon"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "Particle Argon"
 
 #define MICROPY_HW_LED_STATUS          (&pin_P1_12)
 
diff --git a/ports/nrf/boards/particle_boron/mpconfigboard.h b/ports/nrf/boards/particle_boron/mpconfigboard.h
index 5e817311f9..af69924841 100644
--- a/ports/nrf/boards/particle_boron/mpconfigboard.h
+++ b/ports/nrf/boards/particle_boron/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Particle Boron"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "Particle Boron"
 
 #define MICROPY_HW_LED_STATUS          (&pin_P1_12)
 
diff --git a/ports/nrf/boards/particle_xenon/mpconfigboard.h b/ports/nrf/boards/particle_xenon/mpconfigboard.h
index 6c8cc7cef2..34ca6421e6 100644
--- a/ports/nrf/boards/particle_xenon/mpconfigboard.h
+++ b/ports/nrf/boards/particle_xenon/mpconfigboard.h
@@ -29,7 +29,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "Particle Xenon"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "Particle Xenon"
 
 #define MICROPY_HW_LED_STATUS          (&pin_P1_12)
 
diff --git a/ports/nrf/boards/pca10056/mpconfigboard.h b/ports/nrf/boards/pca10056/mpconfigboard.h
index 48ef7f1c39..5b30c7fe83 100644
--- a/ports/nrf/boards/pca10056/mpconfigboard.h
+++ b/ports/nrf/boards/pca10056/mpconfigboard.h
@@ -28,7 +28,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "PCA10056 nRF52840-DK"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "nRF52840-DK"
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
diff --git a/ports/nrf/boards/pca10059/mpconfigboard.h b/ports/nrf/boards/pca10059/mpconfigboard.h
index d5ce212292..b79d3c88f2 100644
--- a/ports/nrf/boards/pca10059/mpconfigboard.h
+++ b/ports/nrf/boards/pca10059/mpconfigboard.h
@@ -26,7 +26,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "PCA10059 nRF52840 Dongle"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "nRF52840-DK"
 
 #define MICROPY_HW_LED_STATUS          (&pin_P0_06)
 
diff --git a/ports/nrf/boards/sparkfun_nrf52840_mini/mpconfigboard.h b/ports/nrf/boards/sparkfun_nrf52840_mini/mpconfigboard.h
index a5ed69b2bd..cc7e68864e 100644
--- a/ports/nrf/boards/sparkfun_nrf52840_mini/mpconfigboard.h
+++ b/ports/nrf/boards/sparkfun_nrf52840_mini/mpconfigboard.h
@@ -28,7 +28,6 @@
 
 #define MICROPY_HW_BOARD_NAME       "SparkFun Pro nRF52840 Mini"
 #define MICROPY_HW_MCU_NAME         "nRF52840"
-#define MICROPY_PY_SYS_PLATFORM     "SFE_NRF52840_Mini"
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
diff --git a/ports/nrf/common-hal/busio/I2C.c b/ports/nrf/common-hal/busio/I2C.c
index 71835d16ad..8a2ebde3bd 100644
--- a/ports/nrf/common-hal/busio/I2C.c
+++ b/ports/nrf/common-hal/busio/I2C.c
@@ -28,13 +28,12 @@
  */
 
 #include "shared-bindings/busio/I2C.h"
+#include "shared-bindings/microcontroller/__init__.h"
 #include "py/mperrno.h"
 #include "py/runtime.h"
 #include "supervisor/shared/translate.h"
 
 #include "nrfx_twim.h"
-#include "nrf_gpio.h"
-
 #include "nrfx_spim.h"
 #include "nrf_gpio.h"
 
@@ -107,7 +106,7 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *
     for (size_t i = 0 ; i < MP_ARRAY_SIZE(twim_peripherals); i++) {
         if (!twim_peripherals[i].in_use) {
             self->twim_peripheral = &twim_peripherals[i];
-            self->twim_peripheral->in_use = true;
+            // Mark it as in_use later after other validation is finished.
             break;
         }
     }
@@ -116,10 +115,27 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *
         mp_raise_ValueError(translate("All I2C peripherals are in use"));
     }
 
+    // Test that the pins are in a high state. (Hopefully indicating they are pulled up.)
+    nrf_gpio_cfg_input(scl->number, NRF_GPIO_PIN_PULLDOWN);
+    nrf_gpio_cfg_input(sda->number, NRF_GPIO_PIN_PULLDOWN);
+
+    common_hal_mcu_delay_us(10);
+
+    nrf_gpio_cfg_input(scl->number, NRF_GPIO_PIN_NOPULL);
+    nrf_gpio_cfg_input(sda->number, NRF_GPIO_PIN_NOPULL);
+
+    // We must pull up within 3us to achieve 400khz.
+    common_hal_mcu_delay_us(3);
+
+    if (!nrf_gpio_pin_read(sda->number) || !nrf_gpio_pin_read(scl->number)) {
+        reset_pin_number(sda->number);
+        reset_pin_number(scl->number);
+        mp_raise_RuntimeError(translate("SDA or SCL needs a pull up"));
+    }
+
     nrfx_twim_config_t config = NRFX_TWIM_DEFAULT_CONFIG;
     config.scl = scl->number;
     config.sda = sda->number;
-
     // change freq. only if it's less than the default 400K
     if (frequency < 100000) {
         config.frequency = NRF_TWIM_FREQ_100K;
@@ -132,6 +148,8 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *
     claim_pin(sda);
     claim_pin(scl);
 
+    // About to init. If we fail after this point, common_hal_busio_i2c_deinit() will set in_use to false.
+    self->twim_peripheral->in_use = true;
     nrfx_err_t err = nrfx_twim_init(&self->twim_peripheral->twim, &config, NULL, NULL);
 
     // A soft reset doesn't uninit the driver so we might end up with a invalid state
@@ -152,8 +170,9 @@ bool common_hal_busio_i2c_deinited(busio_i2c_obj_t *self) {
 }
 
 void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
-    if (common_hal_busio_i2c_deinited(self))
+    if (common_hal_busio_i2c_deinited(self)) {
         return;
+    }
 
     nrfx_twim_uninit(&self->twim_peripheral->twim);
 
diff --git a/ports/nrf/common-hal/microcontroller/Pin.c b/ports/nrf/common-hal/microcontroller/Pin.c
index 3cee784b63..ce55317e54 100644
--- a/ports/nrf/common-hal/microcontroller/Pin.c
+++ b/ports/nrf/common-hal/microcontroller/Pin.c
@@ -25,6 +25,7 @@
  */
 
 #include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
 
 #include "nrf_gpio.h"
 #include "py/mphal.h"
@@ -47,6 +48,19 @@ bool speaker_enable_in_use;
 STATIC uint32_t claimed_pins[GPIO_COUNT];
 STATIC uint32_t never_reset_pins[GPIO_COUNT];
 
+STATIC void reset_speaker_enable_pin(void) {
+#ifdef SPEAKER_ENABLE_PIN
+    speaker_enable_in_use = false;
+    nrf_gpio_cfg(SPEAKER_ENABLE_PIN->number,
+                 NRF_GPIO_PIN_DIR_OUTPUT,
+                 NRF_GPIO_PIN_INPUT_DISCONNECT,
+                 NRF_GPIO_PIN_NOPULL,
+                 NRF_GPIO_PIN_H0H1,
+                 NRF_GPIO_PIN_NOSENSE);
+    nrf_gpio_pin_write(SPEAKER_ENABLE_PIN->number, false);
+#endif
+}
+
 void reset_all_pins(void) {
     for (size_t i = 0; i < GPIO_COUNT; i++) {
         claimed_pins[i] = never_reset_pins[i];
@@ -68,10 +82,7 @@ void reset_all_pins(void) {
     #endif
 
     // After configuring SWD because it may be shared.
-    #ifdef SPEAKER_ENABLE_PIN
-    speaker_enable_in_use = false;
-    // TODO set pin to out and turn off.
-    #endif
+    reset_speaker_enable_pin();
 }
 
 // Mark pin as free and return it to a quiescent state.
@@ -91,8 +102,8 @@ void reset_pin_number(uint8_t pin_number) {
     }
     #endif
     #ifdef MICROPY_HW_APA102_MOSI
-    if (pin == MICROPY_HW_APA102_MOSI->number ||
-        pin == MICROPY_HW_APA102_SCK->number) {
+    if (pin_number == MICROPY_HW_APA102_MOSI->number ||
+        pin_number == MICROPY_HW_APA102_SCK->number) {
         apa102_mosi_in_use = apa102_mosi_in_use && pin_number != MICROPY_HW_APA102_MOSI->number;
         apa102_sck_in_use = apa102_sck_in_use && pin_number != MICROPY_HW_APA102_SCK->number;
         if (!apa102_sck_in_use && !apa102_mosi_in_use) {
@@ -104,10 +115,7 @@ void reset_pin_number(uint8_t pin_number) {
 
     #ifdef SPEAKER_ENABLE_PIN
     if (pin_number == SPEAKER_ENABLE_PIN->number) {
-        speaker_enable_in_use = false;
-        common_hal_digitalio_digitalinout_switch_to_output(SPEAKER_ENABLE_PIN, true, DRIVE_MODE_PUSH_PULL);
-        nrf_gpio_pin_dir_set(pin_number, NRF_GPIO_PIN_DIR_OUTPUT);
-        nrf_gpio_pin_write(pin_number, false);
+        reset_speaker_enable_pin();
     }
     #endif
 }
diff --git a/ports/nrf/mpconfigport.h b/ports/nrf/mpconfigport.h
index 0b755a156b..bbe6419a5f 100644
--- a/ports/nrf/mpconfigport.h
+++ b/ports/nrf/mpconfigport.h
@@ -30,6 +30,10 @@
 
 #include "ble_drv.h"
 
+#ifdef NRF52840
+#define MICROPY_PY_SYS_PLATFORM "nRF52840"
+#endif
+
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT       (1)
 #define MICROPY_PY_FUNCTION_ATTRS                (1)
 #define MICROPY_PY_IO                            (1)
diff --git a/ports/nrf/nrfx_config.h b/ports/nrf/nrfx_config.h
index 8fa6721e2c..cafec6aa1d 100644
--- a/ports/nrf/nrfx_config.h
+++ b/ports/nrf/nrfx_config.h
@@ -5,12 +5,9 @@
 #define NRFX_POWER_ENABLED 1
 #define NRFX_POWER_CONFIG_IRQ_PRIORITY 7
 
-// Turn on nrfx supported workarounds for errata in Rev1/Rev2 of nRF52832
-#ifdef NRF52832_XXAA
-    #define NRFX_SPIS_NRF52_ANOMALY_109_WORKAROUND_ENABLED 1
-#endif
-
-// NOTE: THIS WORKAROUND CAUSES BLE CODE TO CRASH; tested on 2019-03-11.
+// NOTE: THIS WORKAROUND CAUSES BLE CODE TO CRASH.
+// It doesn't work with the SoftDevice.
+// See https://devzone.nordicsemi.com/f/nordic-q-a/33982/sdk-15-software-crash-during-spi-session
 // Turn on nrfx supported workarounds for errata in Rev1 of nRF52840
 #ifdef NRF52840_XXAA
 //    #define NRFX_SPIM3_NRF52840_ANOMALY_198_WORKAROUND_ENABLED 1
@@ -24,11 +21,26 @@
 // so out of the box TWIM0/SPIM0 and TWIM1/SPIM1 cannot be shared
 // between common-hal/busio/I2C.c and SPI.c.
 // We could write an interrupt handler that checks whether it's
-// being used for SPI or I2C, but perhaps two I2C's and 1-2 SPI's are good enough for now.
+// being used for SPI or I2C, but perhaps one I2C and two SPI or two I2C and one SPI
+// are good enough for now.
+
+// CIRCUITPY_NRF_NUM_I2C is 1 or 2 to choose how many I2C (TWIM) peripherals
+// to provide.
+// This can go away once we have SPIM3 working: then we can have two
+// I2C and two SPI.
+#ifndef CIRCUITPY_NRF_NUM_I2C
+#define CIRCUITPY_NRF_NUM_I2C 1
+#endif
+
+#if CIRCUITPY_NRF_NUM_I2C != 1 && CIRCUITPY_NRF_NUM_I2C != 2
+# error CIRCUITPY_NRF_NUM_I2C must be 1 or 2
+#endif
 
 // Enable SPIM1, SPIM2 and SPIM3 (if available)
 // No conflict with TWIM0.
+#if CIRCUITPY_NRF_NUM_I2C == 1
 #define NRFX_SPIM1_ENABLED 1
+#endif
 #define NRFX_SPIM2_ENABLED 1
 // DON'T ENABLE SPIM3 DUE TO ANOMALY WORKAROUND FAILURE (SEE ABOVE).
 // #ifdef NRF52840_XXAA
@@ -45,10 +57,13 @@
 // QSPI
 #define NRFX_QSPI_ENABLED                          1
 
-// TWI aka. I2C; enable a single bus: TWIM0 (no conflict with SPIM1 and SPIM2)
+// TWI aka. I2C; always enable TWIM0 (no conflict with SPIM1 and SPIM2)
 #define NRFX_TWIM_ENABLED 1
 #define NRFX_TWIM0_ENABLED 1
-//#define NRFX_TWIM1_ENABLED 1
+
+#if CIRCUITPY_NRF_NUM_I2C == 2
+#define NRFX_TWIM1_ENABLED 1
+#endif
 
 #define NRFX_TWIM_DEFAULT_CONFIG_IRQ_PRIORITY 7
 #define NRFX_TWIM_DEFAULT_CONFIG_FREQUENCY NRF_TWIM_FREQ_400K
diff --git a/shared-bindings/_bleio/Service.c b/shared-bindings/_bleio/Service.c
index da5633f2a3..c9b8288070 100644
--- a/shared-bindings/_bleio/Service.c
+++ b/shared-bindings/_bleio/Service.c
@@ -49,7 +49,7 @@
 //|
 //|   .. classmethod:: add_to_peripheral(peripheral, uuid, *, secondary=False)
 //|
-//|     Create a new Service object, identitied by the specified UUID, and add it
+//|     Create a new Service object, identified by the specified UUID, and add it
 //|     to the given Peripheral.
 //|
 //|     To mark the service as secondary, pass `True` as :py:data:`secondary`.
diff --git a/shared-bindings/_pixelbuf/__init__.c b/shared-bindings/_pixelbuf/__init__.c
index 48b9f1cef1..eb0cb29842 100644
--- a/shared-bindings/_pixelbuf/__init__.c
+++ b/shared-bindings/_pixelbuf/__init__.c
@@ -55,7 +55,7 @@
 
 //| .. class:: ByteOrder()
 //|
-//|   Classes representing byteorders for circuitpython
+//|   Classes representing byteorders for CircuitPython
 
 
 //|   .. attribute:: bpp
@@ -284,7 +284,7 @@ PIXELBUF_BYTEORDER(LBRG, 4, 3, 1, 2, 0, false, true)
 //|    * **bpp** 4
 //|    * **has_luminosity** True
 //|
-//|    Actual format commonly used by DotStar (5 bit luninance value)
+//|    Actual format commonly used by DotStar (5 bit luminance value)
 PIXELBUF_BYTEORDER(LBGR, 4, 3, 2, 1, 0, false, true)
 
 STATIC const mp_rom_map_elem_t pixelbuf_module_globals_table[] = {
diff --git a/shared-bindings/audiobusio/I2SOut.c b/shared-bindings/audiobusio/I2SOut.c
index 2cd2b67289..81383c7776 100644
--- a/shared-bindings/audiobusio/I2SOut.c
+++ b/shared-bindings/audiobusio/I2SOut.c
@@ -62,7 +62,7 @@
 //|     import time
 //|     import math
 //|
-//|     # Generate one period of sine wav.
+//|     # Generate one period of sine wave.
 //|     length = 8000 // 440
 //|     sine_wave = array.array("H", [0] * length)
 //|     for i in range(length):
diff --git a/shared-bindings/audioio/__init__.c b/shared-bindings/audioio/__init__.c
index 7fa37d5c51..02a5fe1eee 100644
--- a/shared-bindings/audioio/__init__.c
+++ b/shared-bindings/audioio/__init__.c
@@ -68,7 +68,7 @@
 //|
 //| For compatibility with CircuitPython 4.x, some builds allow the items in
 //| `audiocore` to be imported from `audioio`.  This will be removed for all
-//| boards in a future build of CicuitPython.
+//| boards in a future build of CircuitPython.
 //|
 
 STATIC const mp_rom_map_elem_t audioio_module_globals_table[] = {
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
index 3bd89e2e20..50a95beb2e 100644
--- a/shared-bindings/busio/I2C.c
+++ b/shared-bindings/busio/I2C.c
@@ -60,6 +60,10 @@
 //|   :param int frequency: The clock frequency in Hertz
 //|   :param int timeout: The maximum clock stretching timeut - (used only for bitbangio.I2C; ignored for busio.I2C)
 //|
+//|   .. note:: On the nRF52840, only one I2C object may be created,
+//|      except on the Circuit Playground Bluefruit, which allows two,
+//|      one for the onboard accelerometer, and one for offboard use.
+//|
 STATIC mp_obj_t busio_i2c_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     busio_i2c_obj_t *self = m_new_obj(busio_i2c_obj_t);
     self->base.type = &busio_i2c_type;
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
index d47bf499a2..d1791bef3b 100644
--- a/shared-bindings/busio/SPI.c
+++ b/shared-bindings/busio/SPI.c
@@ -154,11 +154,12 @@ STATIC void check_for_deinit(busio_spi_obj_t *self) {
 //|      within spec for the SAMD21.
 //|
 //|   .. note:: On the nRF52840, these baudrates are available: 125kHz, 250kHz, 1MHz, 2MHz, 4MHz,
-//|      and 8MHz. 16MHz and 32MHz are also available, but only on the first
-//|      `busio.SPI` object you create. Two more ``busio.SPI`` objects can be created, but they are restricted
-//|      to 8MHz maximum. This is a hardware restriction: there is only one high-speed SPI peripheral.
+//|      and 8MHz.
 //|      If you pick a a baudrate other than one of these, the nearest lower
 //|      baudrate will be chosen, with a minimum of 125kHz.
+//|      Two SPI objects may be created, except on the Circuit Playground Bluefruit,
+//|      which allows only one (to allow for an additional I2C object).
+//|
 STATIC mp_obj_t busio_spi_configure(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits };
     static const mp_arg_t allowed_args[] = {
diff --git a/shared-bindings/pulseio/PWMOut.c b/shared-bindings/pulseio/PWMOut.c
index 40981e0a81..53b88c61a5 100644
--- a/shared-bindings/pulseio/PWMOut.c
+++ b/shared-bindings/pulseio/PWMOut.c
@@ -162,6 +162,11 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pulseio_pwmout___exit___obj, 4, 4, pu
 //|      16 bit value that dictates how much of one cycle is high (1) versus low
 //|      (0). 0xffff will always be high, 0 will always be low and 0x7fff will
 //|      be half high and then half low.
+//|
+//|      Depending on how PWM is implemented on a specific board, the internal
+//|      representation for duty cycle might have less than 16 bits of resolution.
+//|      Reading this property will return the value from the internal representation,
+//|      so it may differ from the value set.
 STATIC mp_obj_t pulseio_pwmout_obj_get_duty_cycle(mp_obj_t self_in) {
     pulseio_pwmout_obj_t *self = MP_OBJ_TO_PTR(self_in);
     check_for_deinit(self);
@@ -193,6 +198,12 @@ const mp_obj_property_t pulseio_pwmout_duty_cycle_obj = {
 //|     32 bit value that dictates the PWM frequency in Hertz (cycles per
 //|     second). Only writeable when constructed with ``variable_frequency=True``.
 //|
+//|     Depending on how PWM is implemented on a specific board, the internal value
+//|     for the PWM's duty cycle may need to be recalculated when the frequency
+//|     changes. In these cases, the duty cycle is automatically recalculated
+//|     from the original duty cycle value. This should happen without any need
+//|     to manually re-set the duty cycle.
+//|
 STATIC mp_obj_t pulseio_pwmout_obj_get_frequency(mp_obj_t self_in) {
     pulseio_pwmout_obj_t *self = MP_OBJ_TO_PTR(self_in);
     check_for_deinit(self);
diff --git a/shared-bindings/rtc/RTC.c b/shared-bindings/rtc/RTC.c
index 17dccdb03c..3ff09a4ec5 100644
--- a/shared-bindings/rtc/RTC.c
+++ b/shared-bindings/rtc/RTC.c
@@ -57,7 +57,23 @@ STATIC mp_obj_t rtc_rtc_make_new(const mp_obj_type_t *type, size_t n_args, const
 
 //|   .. attribute:: datetime
 //|
-//|       The date and time of the RTC.
+//|       The current date and time of the RTC as a `time.struct_time`.
+//|
+//|       This must be set to the current date and time whenever the board loses power::
+//|
+//|         import rtc
+//|         import time
+//|
+//|         r = rtc.RTC()
+//|         r.datetime = rtctime.struct_time((2019, 5, 29, 15, 14, 15, 0, -1, -1))
+//|
+//|
+//|       Once set, the RTC will automatically update this value as time passes. You can read this
+//|       property to get a snapshot of the current time::
+//|
+//|         current_time = r.datetime
+//|         print(current_time)
+//|         # struct_time(tm_year=2019, tm_month=5, ...)
 //|
 STATIC mp_obj_t rtc_rtc_obj_get_datetime(mp_obj_t self_in) {
     timeutils_struct_time_t tm;
@@ -83,9 +99,10 @@ const mp_obj_property_t rtc_rtc_datetime_obj = {
 
 //|   .. attribute:: calibration
 //|
-//|     The RTC calibration value.
+//|     The RTC calibration value as an `int`.
+//|
 //|     A positive value speeds up the clock and a negative value slows it down.
-//|     Range and value is hardware specific, but one step is often approx. 1 ppm.
+//|     Range and value is hardware specific, but one step is often approximately 1 ppm.
 //|
 STATIC mp_obj_t rtc_rtc_obj_get_calibration(mp_obj_t self_in) {
     int calibration = common_hal_rtc_get_calibration();
diff --git a/shared-bindings/rtc/__init__.c b/shared-bindings/rtc/__init__.c
index ac67a7131c..22eda9b663 100644
--- a/shared-bindings/rtc/__init__.c
+++ b/shared-bindings/rtc/__init__.c
@@ -36,12 +36,13 @@
 //|
 //| .. module:: rtc
 //|   :synopsis: Real Time Clock
-//|   :platform: SAMD21
+//|   :platform: SAMD21, SAMD51, nRF52
 //|
-//| The `rtc` module provides support for a Real Time Clock.
-//| It also backs the `time.time()` and `time.localtime()` functions using the onboard RTC if present.
+//| The `rtc` module provides support for a Real Time Clock. You can access and manage the
+//| RTC using :class:`rtc.RTC`. It also backs the :func:`time.time` and :func:`time.localtime`
+//| functions using the onboard RTC if present.
 //|
-//| Libraries
+//| Classes
 //|
 //| .. toctree::
 //|     :maxdepth: 3
@@ -63,10 +64,9 @@ mp_obj_t rtc_get_time_source_time(void) {
 
 //| .. function:: set_time_source(rtc)
 //|
-//|   Sets the rtc time source used by time.localtime().
-//|   The default is `rtc.RTC()`.
-//|
-//|   Example usage::
+//|   Sets the RTC time source used by :func:`time.localtime`.
+//|   The default is :class:`rtc.RTC`, but it's useful to use this to override the
+//|   time source for testing purposes. For example::
 //|
 //|     import rtc
 //|     import time
diff --git a/shared-module/bitbangio/SPI.c b/shared-module/bitbangio/SPI.c
index 6d3a285231..d02adf34fb 100644
--- a/shared-module/bitbangio/SPI.c
+++ b/shared-module/bitbangio/SPI.c
@@ -43,6 +43,8 @@ void shared_module_bitbangio_spi_construct(bitbangio_spi_obj_t *self,
     if (result != DIGITALINOUT_OK) {
         mp_raise_ValueError(translate("Clock pin init failed."));
     }
+    common_hal_digitalio_digitalinout_switch_to_output(&self->clock, self->polarity == 1, DRIVE_MODE_PUSH_PULL);
+
     if (mosi != mp_const_none) {
         result = common_hal_digitalio_digitalinout_construct(&self->mosi, mosi);
         if (result != DIGITALINOUT_OK) {
@@ -50,8 +52,11 @@ void shared_module_bitbangio_spi_construct(bitbangio_spi_obj_t *self,
             mp_raise_ValueError(translate("MOSI pin init failed."));
         }
         self->has_mosi = true;
+        common_hal_digitalio_digitalinout_switch_to_output(&self->mosi, false, DRIVE_MODE_PUSH_PULL);
     }
+
     if (miso != mp_const_none) {
+        // Starts out as input by default, no need to change.
         result = common_hal_digitalio_digitalinout_construct(&self->miso, miso);
         if (result != DIGITALINOUT_OK) {
             common_hal_digitalio_digitalinout_deinit(&self->clock);
diff --git a/supervisor/shared/rgb_led_colors.h b/supervisor/shared/rgb_led_colors.h
index 48994ad62c..c723fbab36 100644
--- a/supervisor/shared/rgb_led_colors.h
+++ b/supervisor/shared/rgb_led_colors.h
@@ -1,12 +1,18 @@
-#define BLACK   0x000000
-#define GREEN   0x003000
-#define BLUE    0x000030
-#define CYAN    0x003030
-#define RED     0x300000
-#define ORANGE  0x302000
-#define YELLOW  0x303000
-#define PURPLE  0x300030
-#define WHITE   0x303030
+
+#define COLOR(r, g, b) (((r) << 16) | ((g) << 8) | (b))
+// For brightness == 255 (full). This will be adjusted downward for various different RGB indicators,
+// which vary in brightness.
+#define INTENSITY (0x30)
+
+#define BLACK   COLOR(0, 0, 0)
+#define GREEN   COLOR(0, INTENSITY, 0)
+#define BLUE    COLOR(0, 0, INTENSITY)
+#define CYAN    COLOR(0, INTENSITY, INTENSITY)
+#define RED     COLOR(INTENSITY, 0, 0)
+#define ORANGE  COLOR(INTENSITY, INTENSITY*2/3, 0)
+#define YELLOW  COLOR(INTENSITY, INTENSITY, 0)
+#define PURPLE  COLOR(INTENSITY, 0, INTENSITY)
+#define WHITE   COLOR(INTENSITY, INTENSITY, INTENSITY)
 
 #define BOOT_RUNNING BLUE
 #define MAIN_RUNNING GREEN
diff --git a/supervisor/shared/rgb_led_status.c b/supervisor/shared/rgb_led_status.c
index 4d93715161..05df4c628a 100644
--- a/supervisor/shared/rgb_led_status.c
+++ b/supervisor/shared/rgb_led_status.c
@@ -38,7 +38,7 @@ static digitalio_digitalinout_obj_t status_neopixel;
 
 
 #if defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)
-uint8_t rgb_status_brightness = 255;
+uint8_t rgb_status_brightness = 50;
 
 #define APA102_BUFFER_LENGTH 12
 static uint8_t status_apa102_color[APA102_BUFFER_LENGTH] = {0, 0, 0, 0, 0xff, 0, 0, 0, 0xff, 0xff, 0xff, 0xff};
@@ -46,10 +46,18 @@ static uint8_t status_apa102_color[APA102_BUFFER_LENGTH] = {0, 0, 0, 0, 0xff, 0,
 #if CIRCUITPY_BITBANG_APA102
 #include "shared-bindings/bitbangio/SPI.h"
 #include "shared-module/bitbangio/types.h"
-static bitbangio_spi_obj_t status_apa102;
+static bitbangio_spi_obj_t status_apa102 = {
+    .base = {
+        .type = &bitbangio_spi_type,
+    },
+};
 #else
 #include "shared-bindings/busio/SPI.h"
-busio_spi_obj_t status_apa102;
+busio_spi_obj_t status_apa102 = {
+    .base = {
+        .type = &busio_spi_type,
+    },
+};
 #endif
 #endif
 
@@ -59,9 +67,21 @@ busio_spi_obj_t status_apa102;
 #include "shared-bindings/pulseio/PWMOut.h"
 #include "shared-bindings/microcontroller/Pin.h"
 
-pulseio_pwmout_obj_t rgb_status_r;
-pulseio_pwmout_obj_t rgb_status_g;
-pulseio_pwmout_obj_t rgb_status_b;
+pulseio_pwmout_obj_t rgb_status_r = {
+    .base = {
+        .type = &pulseio_pwmout_type,
+    },
+};
+pulseio_pwmout_obj_t rgb_status_g = {
+    .base = {
+        .type = &pulseio_pwmout_type,
+    },
+};
+pulseio_pwmout_obj_t rgb_status_b = {
+    .base = {
+        .type = &pulseio_pwmout_type,
+    },
+};
 
 uint8_t rgb_status_brightness = 0xFF;
 
@@ -74,8 +94,14 @@ uint16_t status_rgb_color[3] = {
 static uint32_t current_status_color = 0;
 #endif
 
-
+static bool rgb_led_status_init_in_progress = false;
 void rgb_led_status_init() {
+    if (rgb_led_status_init_in_progress) {
+        // Avoid recursion.
+        return;
+    }
+    rgb_led_status_init_in_progress = true;
+
     #ifdef MICROPY_HW_NEOPIXEL
         common_hal_digitalio_digitalinout_construct(&status_neopixel, MICROPY_HW_NEOPIXEL);
         // Pretend we aren't using the pins. digitalio.DigitalInOut
@@ -91,15 +117,15 @@ void rgb_led_status_init() {
                                               mp_const_none);
         #else
         if (!common_hal_busio_spi_deinited(&status_apa102)) {
-            // Don't use spi_deinit because that leads to infinite
-            // recursion because reset_pin_number may call
-            // rgb_led_status_init.
-            spi_m_sync_disable(&status_apa102.spi_desc);
+            // This may call us recursively if reset_pin_number() is called,
+            // The rgb_led_status_init_in_progress guard will prevent further recursion.
+            common_hal_busio_spi_deinit(&status_apa102);
         }
         common_hal_busio_spi_construct(&status_apa102,
                                       MICROPY_HW_APA102_SCK,
                                       MICROPY_HW_APA102_MOSI,
                                       mp_const_none);
+        common_hal_busio_spi_never_reset(&status_apa102);
         #endif
         // Pretend we aren't using the pins. bitbangio.SPI will
         // mark them as used.
@@ -149,6 +175,8 @@ void rgb_led_status_init() {
     current_status_color = 0x1000000; // Not a valid color
     new_status_color(rgb);
     #endif
+
+    rgb_led_status_init_in_progress = false;
 }
 
 void reset_status_led() {