atmel-samd: Introduce board reset mechanic used on CircuitPlayground

Express to ensure the Neopixels are off after reloads.

atmel-samd/boards/arduino_zero/board.c

@@ -44,3 +44,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/board.h

@@ -39,4 +39,7 @@ void board_init(void);
 // way.
 bool board_requests_safe_mode(void);
 
+// Reset the state of off MCU components such as neopixels.
+void reset_board(void);
+
 #endif  // __MICROPY_INCLUDED_ATMEL_SAMD_BOARDS_BOARD_H__

atmel-samd/boards/circuitplayground_express/board.c

@@ -24,9 +24,14 @@
  * THE SOFTWARE.
  */
 
+#include <string.h>
+
 #include "boards/board.h"
 #include "asf/sam0/drivers/port/port.h"
 #include "common-hal/microcontroller/Pin.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/neopixel_write/__init__.h"
+#include "samd21_pins.h"
 
 void board_init(void)
 {
@@ -47,3 +52,14 @@ bool board_requests_safe_mode(void) {
     reset_pin(PIN_PA28);
     return safe_mode;
 }
+
+void reset_board(void) {
+    uint8_t empty[30];
+    memset(empty, 0, 30);
+    digitalio_digitalinout_obj_t neopixel_pin;
+    common_hal_digitalio_digitalinout_construct(&neopixel_pin, &pin_PB23);
+    common_hal_digitalio_digitalinout_switch_to_output(&neopixel_pin, false,
+        DRIVE_MODE_PUSH_PULL);
+    common_hal_neopixel_write(&neopixel_pin, empty, 30);
+    common_hal_digitalio_digitalinout_deinit(&neopixel_pin);
+}

atmel-samd/boards/feather_m0_adalogger/board.c

@@ -33,3 +33,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/feather_m0_basic/board.c

@@ -33,3 +33,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/feather_m0_express/board.c

@@ -33,3 +33,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/gemma_m0/board.c

@@ -33,3 +33,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/metro_m0_express/board.c

@@ -44,3 +44,6 @@ void board_init(void)
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/boards/trinket_m0/board.c

@@ -26,10 +26,12 @@
 
 #include "boards/board.h"
 
-void board_init(void)
-{
+void board_init(void) {
 }
 
 bool board_requests_safe_mode(void) {
     return false;
 }
+
+void reset_board(void) {
+}

atmel-samd/main.c

@@ -594,6 +594,7 @@ int main(void) {
 
     // Reset everything and prep MicroPython to run boot.py.
     reset_samd21();
+    reset_board();
     reset_mp();
 
     // Turn on autoreload by default but before boot.py in case it wants to change it.
@@ -656,6 +657,7 @@ int main(void) {
                 autoreload_enable();
             }
             reset_samd21();
+            reset_board();
             reset_mp();
         }
         if (exit_code == PYEXEC_FORCED_EXIT) {
@@ -665,6 +667,7 @@ int main(void) {
             first_run = false;
             skip_repl = start_mp(safe_mode);
             reset_samd21();
+            reset_board();
             reset_mp();
         } else if (exit_code != 0) {
             break;