boards/arduino-common: use software interrupt for context swap

boards/arduino-common/include/board.h

@@ -53,6 +53,20 @@ extern "C" {
 #define LED0_TOGGLE         (PORTB ^=  LED0_MASK)
 /** @} */
 
+/**
+ ** Context swap defines
+ ** Setup to use PJ6 which is pin change interrupt 15 (PCINT15)
+ ** This emulates a software triggered interrupt
+ ***/
+#define AVR_CONTEXT_SWAP_INIT do { \
+            DDRC |= (1 << PC6); \
+            PCICR |= (1 << PCIE1); \
+            PCMSK1 |= (1 << PCINT14); \
+} while (0)
+#define AVR_CONTEXT_SWAP_INTERRUPT_VECT  PCINT1_vect
+#define AVR_CONTEXT_SWAP_TRIGGER   PORTC ^= (1 << PC6)
+
+
 /**
  * @brief xtimer configuration values
  * @{