Common files of Arduino Zero and clones

Detailed Description

Files
file	arduino_iomap.h
	Mapping from MCU pins to Arduino pins.
file	board.h
	Board specific definitions for the Arduino Zero board and clones.
file	gpio_params.h
	Board specific configuration of direct mapped GPIOs.
file	periph_conf.h
	Configuration of CPU peripherals for Arduino Zero board and clones.

xtimer configuration
#define	XTIMER_DEV   TIMER_DEV(1)
#define	XTIMER_CHAN   (0)

LED pin definitions and handlers
#define	LED0_PIN   GPIO_PIN(PA, 17)
#define	LED_PORT   PORT->Group[PA]
#define	LED0_MASK   (1 << 17)
#define	LED0_ON   (LED_PORT.OUTSET.reg = LED0_MASK)
#define	LED0_OFF   (LED_PORT.OUTCLR.reg = LED0_MASK)
#define	LED0_TOGGLE   (LED_PORT.OUTTGL.reg = LED0_MASK)