merge from upstream and make translate

17 files changed, 294 insertions, 40 deletions

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 9da2c498d..9a461f9d8 100755
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -95,8 +95,7 @@ ifeq ($(DEBUG), 1)
   CFLAGS += -fno-inline -fno-ipa-sra
 else
   CFLAGS += -Os -DNDEBUG
-  # TODO: Test with -flto
-  ### CFLAGS += -flto
+  CFLAGS += -flto -flto-partition=none
 endif
 
 
@@ -185,8 +184,7 @@ SRC_C += \
 # USB source files for nrf52840
 ifeq ($(MCU_SUB_VARIANT),nrf52840)
 SRC_C += \
-	lib/tinyusb/src/portable/nordic/nrf5x/dcd_nrf5x.c \
-	lib/tinyusb/src/portable/nordic/nrf5x/hal_nrf5x.c
+	lib/tinyusb/src/portable/nordic/nrf5x/dcd_nrf5x.c
 endif
 
 SRC_COMMON_HAL_EXPANDED = $(addprefix shared-bindings/, $(SRC_COMMON_HAL)) \
diff --git a/ports/nrf/bluetooth/ble_uart.c b/ports/nrf/bluetooth/ble_uart.c
index 91d10cff1..d83cf3980 100644
--- a/ports/nrf/bluetooth/ble_uart.c
+++ b/ports/nrf/bluetooth/ble_uart.c
@@ -138,9 +138,7 @@ void ble_uart_init(void) {
     m_cccd_enabled = false;
 
     while (!m_cccd_enabled) {
-#ifdef MICROPY_VM_HOOK_LOOP
-    MICROPY_VM_HOOK_LOOP
-#endif
+        RUN_BACKGROUND_TASKS;
     }
 }
 
@@ -150,9 +148,7 @@ bool ble_uart_connected(void) {
 
 char ble_uart_rx_chr(void) {
     while (isBufferEmpty(&m_rx_ring_buffer)) {
-#ifdef MICROPY_VM_HOOK_LOOP
-    MICROPY_VM_HOOK_LOOP
-#endif
+        RUN_BACKGROUND_TASKS;
     }
 
     uint8_t byte;
diff --git a/ports/nrf/common-hal/audiobusio/I2SOut.c b/ports/nrf/common-hal/audiobusio/I2SOut.c
new file mode 100644
index 000000000..8be1fb2f8
--- /dev/null
+++ b/ports/nrf/common-hal/audiobusio/I2SOut.c
@@ -0,0 +1,70 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "common-hal/microcontroller/Pin.h"
+#include "common-hal/audiobusio/I2SOut.h"
+
+#include "py/obj.h"
+#include "py/runtime.h"
+
+void common_hal_audiobusio_i2sout_construct(audiobusio_i2sout_obj_t* self,
+        const mcu_pin_obj_t* bit_clock, const mcu_pin_obj_t* word_select,
+        const mcu_pin_obj_t* data, bool left_justified) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+bool common_hal_audiobusio_i2sout_deinited(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+void common_hal_audiobusio_i2sout_deinit(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+void common_hal_audiobusio_i2sout_play(audiobusio_i2sout_obj_t* self,
+                                       mp_obj_t sample, bool loop) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+void common_hal_audiobusio_i2sout_pause(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+void common_hal_audiobusio_i2sout_resume(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+bool common_hal_audiobusio_i2sout_get_paused(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+void common_hal_audiobusio_i2sout_stop(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
+
+bool common_hal_audiobusio_i2sout_get_playing(audiobusio_i2sout_obj_t* self) {
+    mp_raise_NotImplementedError(NULL);
+}
diff --git a/ports/nrf/common-hal/audiobusio/I2SOut.h b/ports/nrf/common-hal/audiobusio/I2SOut.h
new file mode 100644
index 000000000..01c944e72
--- /dev/null
+++ b/ports/nrf/common-hal/audiobusio/I2SOut.h
@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_NRF_COMMON_HAL_AUDIOBUSIO_I2SOUT_H
+#define MICROPY_INCLUDED_NRF_COMMON_HAL_AUDIOBUSIO_I2SOUT_H
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+} audiobusio_i2sout_obj_t;
+
+#endif // MICROPY_INCLUDED_NRF_COMMON_HAL_AUDIOBUSIO_I2SOUT_H
diff --git a/ports/nrf/common-hal/audiobusio/PDMIn.c b/ports/nrf/common-hal/audiobusio/PDMIn.c
new file mode 100644
index 000000000..a7f9c9d74
--- /dev/null
+++ b/ports/nrf/common-hal/audiobusio/PDMIn.c
@@ -0,0 +1,130 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "common-hal/audiobusio/PDMIn.h"
+#include "shared-bindings/microcontroller/Pin.h"
+
+#include "py/runtime.h"
+
+__attribute__((used))
+NRF_PDM_Type *nrf_pdm = NRF_PDM;
+
+static uint32_t dummy_buffer[4];
+
+void common_hal_audiobusio_pdmin_construct(audiobusio_pdmin_obj_t* self,
+                                           const mcu_pin_obj_t* clock_pin,
+                                           const mcu_pin_obj_t* data_pin,
+                                           uint32_t sample_rate,
+                                           uint8_t bit_depth,
+                                           bool mono,
+                                           uint8_t oversample) {
+    assert_pin_free(clock_pin);
+    assert_pin_free(data_pin);
+    claim_pin(clock_pin);
+    claim_pin(data_pin);
+
+    self->mono = mono;
+    self->clock_pin_number = clock_pin->number;
+    self->data_pin_number = data_pin->number;
+
+    if (sample_rate != 16000) {
+        mp_raise_ValueError(translate("only sample_rate=16000 is supported"));
+    }
+    if (bit_depth != 16) {
+        mp_raise_ValueError(translate("only bit_depth=16 is supported"));
+    }
+    nrf_pdm->PSEL.CLK = self->clock_pin_number;
+    nrf_pdm->PSEL.DIN = self->data_pin_number;
+    nrf_pdm->PDMCLKCTRL = PDM_PDMCLKCTRL_FREQ_Default; // For Ratio64
+    nrf_pdm->RATIO = PDM_RATIO_RATIO_Ratio64;
+    nrf_pdm->GAINL = PDM_GAINL_GAINL_DefaultGain;
+    nrf_pdm->GAINR = PDM_GAINR_GAINR_DefaultGain;
+    nrf_pdm->ENABLE = 1;
+
+    nrf_pdm->SAMPLE.PTR = (uintptr_t)&dummy_buffer;
+    nrf_pdm->SAMPLE.MAXCNT = 1;
+    nrf_pdm->TASKS_START = 1;
+}
+
+bool common_hal_audiobusio_pdmin_deinited(audiobusio_pdmin_obj_t* self) {
+    return !self->clock_pin_number;
+}
+
+void common_hal_audiobusio_pdmin_deinit(audiobusio_pdmin_obj_t* self) {
+    nrf_pdm->ENABLE = 0;
+
+    reset_pin_number(self->clock_pin_number);
+    self->clock_pin_number = 0;
+    reset_pin_number(self->data_pin_number);
+    self->data_pin_number = 0;
+}
+
+uint8_t common_hal_audiobusio_pdmin_get_bit_depth(audiobusio_pdmin_obj_t* self) {
+    return 16;
+}
+
+uint32_t common_hal_audiobusio_pdmin_get_sample_rate(audiobusio_pdmin_obj_t* self) {
+    return 16000;
+}
+
+uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t* self,
+        uint16_t* output_buffer, uint32_t output_buffer_length) {
+    // Note: Adafruit's module has SELECT pulled to GND, which makes the DATA
+    // valid when the CLK is low, therefore it must be sampled on the rising edge.
+    if (self->mono) {
+        nrf_pdm->MODE = PDM_MODE_OPERATION_Stereo | PDM_MODE_EDGE_LeftRising;
+    } else {
+        nrf_pdm->MODE = PDM_MODE_OPERATION_Mono | PDM_MODE_EDGE_LeftRising;
+    }
+
+    // step 1. Redirect to real buffer
+    nrf_pdm->SAMPLE.PTR = (uintptr_t)output_buffer;
+    nrf_pdm->SAMPLE.MAXCNT = output_buffer_length;
+
+    // a delay is the safest simple way to ensure that the above requested sample has started
+    mp_hal_delay_us(200);
+    nrf_pdm->EVENTS_END = 0;
+
+    // step 2. Registers are double buffered, so pre-redirect back to dummy buffer
+    nrf_pdm->SAMPLE.PTR = (uintptr_t)&dummy_buffer;
+    nrf_pdm->SAMPLE.MAXCNT = 1;
+
+    // Step 3. wait for PDM to end
+    while (!nrf_pdm->EVENTS_END) {
+       MICROPY_VM_HOOK_LOOP;
+    }
+
+    // Step 4. They want unsigned
+    for (uint32_t i=0; i<output_buffer_length; i++) {
+        output_buffer[i] += 32768;
+    }
+
+    if (self->mono) {
+        return (output_buffer_length / 2) * 2;
+    } else {
+        return (output_buffer_length / 4) * 4;
+    }
+}
diff --git a/ports/nrf/common-hal/audiobusio/PDMIn.h b/ports/nrf/common-hal/audiobusio/PDMIn.h
new file mode 100644
index 000000000..d921e42ff
--- /dev/null
+++ b/ports/nrf/common-hal/audiobusio/PDMIn.h
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_NRF_COMMON_HAL_AUDIOBUSIO_AUDIOOUT_H
+#define MICROPY_INCLUDED_NRF_COMMON_HAL_AUDIOBUSIO_AUDIOOUT_H
+
+#include "common-hal/microcontroller/Pin.h"
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    uint8_t clock_pin_number, data_pin_number;
+    bool mono;
+} audiobusio_pdmin_obj_t;
+
+#endif
diff --git a/ports/nrf/common-hal/audiobusio/__init__.c b/ports/nrf/common-hal/audiobusio/__init__.c
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/ports/nrf/common-hal/audiobusio/__init__.c
diff --git a/ports/nrf/common-hal/bleio/Central.c b/ports/nrf/common-hal/bleio/Central.c
index d771437d6..3c5d97784 100644
--- a/ports/nrf/common-hal/bleio/Central.c
+++ b/ports/nrf/common-hal/bleio/Central.c
@@ -115,7 +115,7 @@ void common_hal_bleio_central_connect(bleio_central_obj_t *self, bleio_address_o
     }
 
     while (self->waiting_to_connect) {
-        MICROPY_VM_HOOK_LOOP;
+        RUN_BACKGROUND_TASKS;
     }
 
     if (self->conn_handle == BLE_CONN_HANDLE_INVALID) {
diff --git a/ports/nrf/common-hal/bleio/Characteristic.c b/ports/nrf/common-hal/bleio/Characteristic.c
index f8b6ce06c..45e8d2495 100644
--- a/ports/nrf/common-hal/bleio/Characteristic.c
+++ b/ports/nrf/common-hal/bleio/Characteristic.c
@@ -94,7 +94,7 @@ STATIC void characteristic_gatts_notify_indicate(uint16_t handle, uint16_t conn_
         // TX buffer is full
         // We could wait for an event indicating the write is complete, but just retrying is easier.
         if (err_code == NRF_ERROR_RESOURCES) {
-            MICROPY_VM_HOOK_LOOP;
+            RUN_BACKGROUND_TASKS;
             continue;
         }
 
@@ -118,7 +118,7 @@ STATIC void characteristic_gattc_read(bleio_characteristic_obj_t *characteristic
     }
 
     while (m_read_characteristic != NULL) {
-        MICROPY_VM_HOOK_LOOP;
+        RUN_BACKGROUND_TASKS;
     }
 
     ble_drv_remove_event_handler(characteristic_on_gattc_read_rsp_evt, characteristic);
@@ -258,7 +258,7 @@ void common_hal_bleio_characteristic_set_cccd(bleio_characteristic_obj_t *self,
         // Write without reponse will return NRF_ERROR_RESOURCES if too many writes are pending.
         if (err_code == NRF_ERROR_BUSY || err_code == NRF_ERROR_RESOURCES) {
             // We could wait for an event indicating the write is complete, but just retrying is easier.
-            MICROPY_VM_HOOK_LOOP;
+            RUN_BACKGROUND_TASKS;
             continue;
         }
 
diff --git a/ports/nrf/common-hal/bleio/CharacteristicBuffer.c b/ports/nrf/common-hal/bleio/CharacteristicBuffer.c
index a6d834d7d..64ab5e8a7 100644
--- a/ports/nrf/common-hal/bleio/CharacteristicBuffer.c
+++ b/ports/nrf/common-hal/bleio/CharacteristicBuffer.c
@@ -99,7 +99,7 @@ int common_hal_bleio_characteristic_buffer_read(bleio_characteristic_buffer_obj_
 
     // Wait for all bytes received or timeout
     while ( (ringbuf_count(&self->ringbuf) < len) && (ticks_ms - start_ticks < self->timeout_ms) ) {
-        MICROPY_VM_HOOK_LOOP;
+        RUN_BACKGROUND_TASKS;
         // Allow user to break out of a timeout with a KeyboardInterrupt.
         if ( mp_hal_is_interrupted() ) {
             return 0;
diff --git a/ports/nrf/common-hal/busio/UART.c b/ports/nrf/common-hal/busio/UART.c
index b9e9e5538..54a66ddbe 100644
--- a/ports/nrf/common-hal/busio/UART.c
+++ b/ports/nrf/common-hal/busio/UART.c
@@ -235,13 +235,11 @@ size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t
 
     // Wait for all bytes received or timeout
     while ( (ringbuf_count(&self->rbuf) < len) && (ticks_ms - start_ticks < self->timeout_ms) ) {
-#ifdef MICROPY_VM_HOOK_LOOP
-        MICROPY_VM_HOOK_LOOP ;
+        RUN_BACKGROUND_TASKS;
         // Allow user to break out of a timeout with a KeyboardInterrupt.
         if ( mp_hal_is_interrupted() ) {
             return 0;
         }
-#endif
     }
 
     // prevent conflict with uart irq
@@ -271,9 +269,7 @@ size_t common_hal_busio_uart_write (busio_uart_obj_t *self, const uint8_t *data,
 
     // Wait for on-going transfer to complete
     while ( nrfx_uarte_tx_in_progress(self->uarte) && (ticks_ms - start_ticks < self->timeout_ms) ) {
-#ifdef MICROPY_VM_HOOK_LOOP
-        MICROPY_VM_HOOK_LOOP
-#endif
+        RUN_BACKGROUND_TASKS;
     }
 
     // Time up
@@ -295,9 +291,7 @@ size_t common_hal_busio_uart_write (busio_uart_obj_t *self, const uint8_t *data,
     (*errcode) = 0;
 
     while ( nrfx_uarte_tx_in_progress(self->uarte) && (ticks_ms - start_ticks < self->timeout_ms) ) {
-#ifdef MICROPY_VM_HOOK_LOOP
-        MICROPY_VM_HOOK_LOOP
-#endif
+        RUN_BACKGROUND_TASKS;
     }
 
     if ( !nrfx_is_in_ram(data) ) {
diff --git a/ports/nrf/common-hal/neopixel_write/__init__.c b/ports/nrf/common-hal/neopixel_write/__init__.c
index 78e0038e8..3b67778a6 100644
--- a/ports/nrf/common-hal/neopixel_write/__init__.c
+++ b/ports/nrf/common-hal/neopixel_write/__init__.c
@@ -200,9 +200,7 @@ void common_hal_neopixel_write (const digitalio_digitalinout_obj_t* digitalinout
 
         // But we have to wait for the flag to be set.
         while ( !nrf_pwm_event_check(pwm, NRF_PWM_EVENT_SEQEND0) ) {
-#ifdef MICROPY_VM_HOOK_LOOP
-            MICROPY_VM_HOOK_LOOP
-#endif
+            RUN_BACKGROUND_TASKS;
         }
 
         // Before leave we clear the flag for the event.
diff --git a/ports/nrf/common-hal/pulseio/PulseOut.c b/ports/nrf/common-hal/pulseio/PulseOut.c
index be5deca9f..d0433247a 100644
--- a/ports/nrf/common-hal/pulseio/PulseOut.c
+++ b/ports/nrf/common-hal/pulseio/PulseOut.c
@@ -155,9 +155,7 @@ void common_hal_pulseio_pulseout_send(pulseio_pulseout_obj_t* self, uint16_t* pu
     while(pulse_array_index < length) {
         // Do other things while we wait. The interrupts will handle sending the
         // signal.
-        #ifdef MICROPY_VM_HOOK_LOOP
-            MICROPY_VM_HOOK_LOOP
-        #endif
+        RUN_BACKGROUND_TASKS;
     }
 
     nrfx_timer_disable(timer);
diff --git a/ports/nrf/device/nrf52/startup_nrf52840.c b/ports/nrf/device/nrf52/startup_nrf52840.c
index 30634a1b5..8e1c36012 100644
--- a/ports/nrf/device/nrf52/startup_nrf52840.c
+++ b/ports/nrf/device/nrf52/startup_nrf52840.c
@@ -116,7 +116,7 @@ void CRYPTOCELL_IRQHandler       (void) __attribute__ ((weak, alias("Default_Han
 void SPIM3_IRQHandler            (void) __attribute__ ((weak, alias("Default_Handler")));
 void PWM3_IRQHandler             (void) __attribute__ ((weak, alias("Default_Handler")));
 
-const func __Vectors[] __attribute__ ((section(".isr_vector"))) = {
+const func __Vectors[] __attribute__ ((used, section(".isr_vector"))) = {
     (func)&_estack,
     Reset_Handler,
     NMI_Handler,
diff --git a/ports/nrf/mpconfigport.mk b/ports/nrf/mpconfigport.mk
index 57879bbaa..55920b3f4 100644
--- a/ports/nrf/mpconfigport.mk
+++ b/ports/nrf/mpconfigport.mk
@@ -14,9 +14,7 @@ LONGINT_IMPL = MPZ
 CIRCUITPY_AUDIOCORE = 1
 CIRCUITPY_AUDIOIO = 0
 CIRCUITPY_AUDIOPWMIO = 1
-
-# No I2S yet.
-CIRCUITPY_AUDIOBUSIO = 0
+CIRCUITPY_AUDIOBUSIO = 1
 
 # No I2CSlave implementation
 CIRCUITPY_I2CSLAVE = 0
diff --git a/ports/nrf/mphalport.c b/ports/nrf/mphalport.c
index 7d9463d0b..bcd9fb114 100644
--- a/ports/nrf/mphalport.c
+++ b/ports/nrf/mphalport.c
@@ -39,9 +39,7 @@ void mp_hal_delay_ms(mp_uint_t delay) {
     uint64_t start_tick = ticks_ms;
     uint64_t duration = 0;
     while (duration < delay) {
-        #ifdef MICROPY_VM_HOOK_LOOP
-            MICROPY_VM_HOOK_LOOP
-        #endif
+        RUN_BACKGROUND_TASKS;
         // Check to see if we've been CTRL-Ced by autoreload or the user.
         if(MP_STATE_VM(mp_pending_exception) == MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_kbd_exception)) ||
            MP_STATE_VM(mp_pending_exception) == MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_reload_exception))) {
diff --git a/ports/nrf/sd_mutex.c b/ports/nrf/sd_mutex.c
index 7682ffa62..b3162e6af 100644
--- a/ports/nrf/sd_mutex.c
+++ b/ports/nrf/sd_mutex.c
@@ -37,9 +37,7 @@ void sd_mutex_acquire_check(nrf_mutex_t* p_mutex) {
 
 void sd_mutex_acquire_wait(nrf_mutex_t* p_mutex) {
     while (sd_mutex_acquire(p_mutex) == NRF_ERROR_SOC_MUTEX_ALREADY_TAKEN) {
-#ifdef MICROPY_VM_HOOK_LOOP
-    MICROPY_VM_HOOK_LOOP
-#endif
+        RUN_BACKGROUND_TASKS;
     }
 }