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Saturday, January 7, 2012

Timer counter polled example

This is from xilinx examples

====================================================================

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

#include "xparameters.h"
#include "xtmrctr.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 TMRCTR_DEVICE_ID XPAR_TMRCTR_0_DEVICE_ID


/*
 * This example only uses the 1st of the 2 timer counters contained in a
 * single timer counter hardware device
 */
#define TIMER_COUNTER_0 0


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


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


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

int TmrCtrPolledExample(u16 DeviceId, u8 TmrCtrNumber);

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

XTmrCtr TimerCounter; /* The instance of the Tmrctr Device */


/*****************************************************************************/
/**
* Main function to call the polled example.
*
* @param None.
*
* @return XST_SUCCESS to indicate success, else XST_FAILURE to indicate
* a Failure.
*
* @note None.
*
******************************************************************************/
int main(void)
{

int Status;

/*
* Run the Timer Counter - Polled Example
*/
Status = TmrCtrPolledExample(TMRCTR_DEVICE_ID, TIMER_COUNTER_0);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}

return XST_SUCCESS;

}


/*****************************************************************************/
/**
* This function does a minimal test on the timer counter device and
* driver as a design example. The purpose of this function is to illustrate
* how to use the XTmrCtr component in a polled mode.
*
*
* @param DeviceId is the XPAR__DEVICE_ID value from
* xparameters.h
* @param TmrCtrNumber is the timer counter of the device to operate on.
* Each device may contain multiple timer counters.
* The timer number is a zero based number with a range of
* 0 - (XTC_DEVICE_TIMER_COUNT - 1).
*
* @return XST_SUCCESS to indicate success, else XST_FAILURE to indicate
* a Failure.
*
* @note
*
* This function contains a loop which waits for the value of a timer counter
* to change. If the hardware is not working correctly, this function may not
* return.
*
****************************************************************************/
int TmrCtrPolledExample(u16 DeviceId, u8 TmrCtrNumber)
{
int Status;
u32 Value1;
u32 Value2;
XTmrCtr *TmrCtrInstancePtr = &TimerCounter;

/*
* Initialize the timer counter so that it's ready to use,
* specify the device ID that is generated in xparameters.h
*/
Status = XTmrCtr_Initialize(TmrCtrInstancePtr, DeviceId);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}

/*
* Perform a self-test to ensure that the hardware was built
* correctly, use the 1st timer in the device (0)
*/
Status = XTmrCtr_SelfTest(TmrCtrInstancePtr, TmrCtrNumber);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}


/*
* Enable the Autoreload mode of the timer counters.
*/
XTmrCtr_SetOptions(TmrCtrInstancePtr, TmrCtrNumber,
XTC_AUTO_RELOAD_OPTION);

/*
* Get a snapshot of the timer counter value before it's started
* to compare against later
*/
Value1 = XTmrCtr_GetValue(TmrCtrInstancePtr, TmrCtrNumber);

/*
* Start the timer counter such that it's incrementing by default
*/
XTmrCtr_Start(TmrCtrInstancePtr, TmrCtrNumber);

/*
* Read the value of the timer counter and wait for it to change,
* since it's incrementing it should change, if the hardware is not
* working for some reason, this loop could be infinite such that the
* function does not return
*/
while (1) {
Value2 = XTmrCtr_GetValue(TmrCtrInstancePtr, TmrCtrNumber);
if (Value1 != Value2) {
break;
}
}

/*
* Disable the Autoreload mode of the timer counters.
*/
XTmrCtr_SetOptions(TmrCtrInstancePtr, TmrCtrNumber, 0);

return XST_SUCCESS;
}

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