add board_button_read()

hw/bsp/metro_m0_express/board.mk

@@ -19,7 +19,8 @@ SRC_C += \
 	hw/mcu/microchip/samd/asf4/samd21/gcc/system_samd21.c \
 	hw/mcu/microchip/samd/asf4/samd21/hpl/gclk/hpl_gclk.c \
 	hw/mcu/microchip/samd/asf4/samd21/hpl/pm/hpl_pm.c \
-	hw/mcu/microchip/samd/asf4/samd21/hpl/sysctrl/hpl_sysctrl.c
+	hw/mcu/microchip/samd/asf4/samd21/hpl/sysctrl/hpl_sysctrl.c \
+	hw/mcu/microchip/samd/asf4/samd21/hal/src/hal_atomic.c
 
 INC += \
 	-I$(TOP)/hw/mcu/microchip/samd/asf4/samd21/ \

hw/bsp/metro_m0_express/board_metro_m0_express.c

@@ -39,6 +39,7 @@
 // MACRO TYPEDEF CONSTANT ENUM DECLARATION
 //--------------------------------------------------------------------+
 #define LED_PIN      17
+#define BUTTON_PIN   14
 
 /* Referenced GCLKs, should be initialized firstly */
 #define _GCLK_INIT_1ST (1 << 0 | 1 << 1)
@@ -63,6 +64,10 @@ void board_init(void)
   gpio_set_pin_direction(LED_PIN, GPIO_DIRECTION_OUT);
   gpio_set_pin_level(LED_PIN, 0);
 
+  // Button init
+  gpio_set_pin_direction(BUTTON_PIN, GPIO_DIRECTION_IN);
+  gpio_set_pin_pull_mode(BUTTON_PIN, GPIO_PULL_UP);
+
 #if CFG_TUSB_OS  == OPT_OS_NONE
   // 1ms tick timer (samd SystemCoreClock may not correct)
   SysTick_Config(CONF_CPU_FREQUENCY / 1000);
@@ -101,10 +106,12 @@ void board_led_control(bool state)
   gpio_set_pin_level(LED_PIN, state);
 }
 
+uint32_t board_button_read(void)
+{
+  // button is active low
+  return gpio_get_pin_level(BUTTON_PIN) ? 0 : 1;
+}
 
-/*------------------------------------------------------------------*/
-/* TUSB HAL MILLISECOND
- *------------------------------------------------------------------*/
 #if CFG_TUSB_OS  == OPT_OS_NONE
 volatile uint32_t system_ticks = 0;
 
@@ -118,5 +125,4 @@ uint32_t board_millis(void)
   return system_ticks;
 }
 
-
 #endif