Arduino/hardware/arduino/sam/system/CMSIS/Examples/cmsis_example/main.c

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 *         SAM Software Package License
 * ----------------------------------------------------------------------------
 * Copyright (c) 2012, Atmel Corporation
 *
 * All rights reserved.
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 * modification, are permitted provided that the following condition is met:
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/**
 * \brief CMSIS Example
 * \mainpage CMSIS Example
 *
 * \section Purpose
 *
 * The cmsis example will help new users get familiar with
 * basic cmsis utilities of SAM3 and SAM4 microcontrollers.
 *
 * The example will execute the following tests:
 * - The application will flash the LED per second. The second 
 * is calculated by the standard system tick interface of cmsis.
 *
 * \section Requirements
 *
 * This package can be used with SAM3 and SAM4 evaluation kits.
 *
 * \section Description
 * The cmsis example will use the system tick of the Cortex-M.
 *
 * \section Usage
 *
 * -# Build the program and download it into the evaluation board. Please
 *    refer to the
 *    <a href="http://www.atmel.com/dyn/resources/prod_documents/doc6224.pdf">
 *    SAM-BA User Guide</a>, the
 *    <a href="http://www.atmel.com/dyn/resources/prod_documents/doc6310.pdf">
 *    GNU-Based Software Development</a> application note or the
 *    <a href="ftp://ftp.iar.se/WWWfiles/arm/Guides/EWARM_UserGuide.ENU.pdf">
 *    IAR EWARM User Guide</a>, depending on the solutions that users choose.
 *
 */

#include "sam.h"

#include "conf_board.h"

__INLINE static void delay_ms(uint32_t dw_dly_ticks);
__INLINE static void led_config(void);
__INLINE static void led_on(uint32_t dw_led);
__INLINE static void led_off(uint32_t dw_led);

/* Systick Counter */
static volatile uint32_t dw_ms_ticks = 0U;

/**
 * \brief SysTick_Handler.
 */
void SysTick_Handler(void)
{
	/* Increment counter necessary in delay(). */
	dw_ms_ticks++;
}

/**
 * \brief Delay number of tick Systicks (happens every 1 ms).
 */
__INLINE static void delay_ms(uint32_t dw_dly_ticks)
{
	uint32_t dw_cur_ticks;

	dw_cur_ticks = dw_ms_ticks;
	while ((dw_ms_ticks - dw_cur_ticks) < dw_dly_ticks) {
	}
}

 /**
  * \brief Configure LED pins.
  */
__INLINE static void led_config(void)
{
	/* Set up LED pins. */
	LED0_PIO->PIO_PER = LED0_MASK;
	LED0_PIO->PIO_OER = LED0_MASK;
	LED0_PIO->PIO_PUDR = LED0_MASK;
}

/**
 * \brief Switch on LED.
 */
__INLINE static void led_on(uint32_t dw_led)
{
	/* Turn On LED. */
	LED0_PIO->PIO_CODR = dw_led;
}

/**
 * \brief Switch off LED.
 */
__INLINE static void led_off(uint32_t dw_led)
{
	/* Turn Off LED. */
	LED0_PIO->PIO_SODR = dw_led;
}

/**
 * \brief Application entry point.
 *
 * \return Unused (ANSI-C compatibility).
 */
int main(void)
{
	/* Initilize the SAM3 system */
	SystemInit();

	WDT->WDT_MR = WDT_MR_WDDIS;

	/* Set up SysTick Timer for 1 msec interrupts. */
	if (SysTick_Config(SystemCoreClock / (uint32_t) 1000)) {
		/* Capture error. */
		while (1) {
		}
	}

	led_config();

	/* Flash the LED. */
	while (1) {
		/* Turn on the LED. */
		led_on(LED0_MASK);
		/* Delay  1000 Msec. */
		delay_ms((uint32_t) 1000);

		/* Turn off the LED. */
		led_off(LED0_MASK);
		/* Delay  1000 Msec. */
		delay_ms((uint32_t) 1000);
	}
}