embeddedsw/XilinxProcessorIPLib/drivers/wdttb/examples/xwdttb_example.c

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/*****************************************************************************/
/**
* @file  xwdttb_example.c
*
* This file contains a design example using the Watchdog Timer Timebase driver
* (XWdtTb) and hardware device.
*
* @note
*
* None.
*
* MODIFICATION HISTORY:
*
*<pre>
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00b jhl  02/13/02 First release
* 1.00b sv   04/26/05 Minor changes to comply to Doxygen and coding guidelines
* 2.00a ktn  12/02/09 Updated the example to use the HAL APIs/macros.
*		      Updated this example to check for Watchdog timer reset
*		      condition instead of timer expiry state to avoid a race
* 		      condition
*</pre>
******************************************************************************/

/***************************** Include Files *********************************/

#include "xparameters.h"
#include "xwdttb.h"

/************************** Constant Definitions *****************************/

/*
 * The following constants map to the XPAR parameters created in the
 * xparameters.h file. They are only defined here such that a user can easily
 * change all the needed parameters in one place.
 */
#define WDTTB_DEVICE_ID		XPAR_WDTTB_0_DEVICE_ID


/**************************** Type Definitions *******************************/


/***************** Macros (Inline Functions) Definitions *********************/


/************************** Function Prototypes ******************************/

int WdtTbExample(u16 DeviceId);

/************************** Variable Definitions *****************************/

XWdtTb WatchdogTimebase; /* Instance of WatchDog Timer Base */

/*****************************************************************************/
/**
* Main function to call the Wdttb driver example.
*
* @param	None.
*
* @return	XST_SUCCESS if successful, XST_FAILURE if unsuccessful.
*
* @note		None.
*
******************************************************************************/
int main(void)
{
	int Status;

	/*
	 * Call the example , specify the device ID that is generated in
	 * xparameters.h.
	 */
	Status = WdtTbExample(WDTTB_DEVICE_ID);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	return XST_SUCCESS;
}

/*****************************************************************************/
/**
* This function tests the functioning of the TimeBase WatchDog Timer module
* in the polled mode.
*
* After one expiration of the WDT timeout interval, the WDT state bit is set to
* one in the status register. If the state bit is not cleared (by writing a 1 to
* the state bit) before the next expiration of the timeout interval, a WDT reset
* is generated.
*
* This function checks for Watchdog timer reset condition in two timer expiry
* state.
*
* This function may require some time (seconds or even minutes) to execute
* because it waits for the watchdog timer to expire.
*
* @param	DeviceId is the XPAR_<WDTB_instance>_DEVICE_ID value from
*		xparameters.h.
*
* @return	XST_SUCCESS if WRS bit is not set in next two subsequent timer
*		expiry state, otherwise XST_FAILURE.
*
* @note		None.
*
****************************************************************************/
int WdtTbExample(u16 DeviceId)
{
	int Status;
	int Count = 0;

	/*
	 * Initialize the watchdog timer and timebase driver so that
	 * it is ready to use.
	 */
	Status = XWdtTb_Initialize(&WatchdogTimebase, DeviceId);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/*
	 * Perform a self-test to ensure that the hardware was built correctly.
	 */
	Status = XWdtTb_SelfTest(&WatchdogTimebase);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}


	/*
	 * Start the watchdog timer, the timebase is automatically reset
	 * when this occurs.
	 */
	XWdtTb_Start(&WatchdogTimebase);

	/*
	 * Verify Whether the WatchDog Reset Status has been set in the next two
	 * expiry state.
	 */
	while (1) {

		/*
		 * If the watchdog timer expired, then restart it.
		 */
		if (XWdtTb_IsWdtExpired(&WatchdogTimebase)) {

			/*
			 * Restart the watchdog timer as a normal application
			 * would
			 */
			XWdtTb_RestartWdt(&WatchdogTimebase);
			Count++;
		}

		/*
		 * Check whether the WatchDog Reset Status has been set.
		 * If this is set means then the test has failed
		 */
		if (XWdtTb_ReadReg(WatchdogTimebase.RegBaseAddress,
				XWT_TWCSR0_OFFSET) & XWT_CSR0_WRS_MASK) {

			/*
			 * Stop the watchdog timer
			 */
			XWdtTb_Stop(&WatchdogTimebase);
			return XST_FAILURE;
		}

		/*
		 * Check whether the WatchDog timer expires two times.
		 * If the timer expires two times then the test is passed.
		 */
		if(Count == 2) {
			break;
		}
	}
	return XST_SUCCESS;
}