Delay using PIT driver

[anujtanksali]

Hello,

Am using iMXRT1064 controller. I wanted to generate a blocking delay of msec or usec. where can i find the delay routines in the driver code. Any example would help. 

Thanks

Regards

Anuj

[jingpan]

Hi,

Have you download RT1064 SDK. There is PIT example in SDK_2.5.0_EVK-MIMXRT1060\boards\evkmimxrt1060\driver_examples\pit

Regards,

Jing

[anujtanksali]

Hi,

Thanks for the reply. I have gone through the PIT driver but it uses an interrupt when timer count is over. i dont want to use interrupt. 

my ex function would be 

Delayms(1000)

{

   loop 1000 times

    {

         call pit driver function which will wait for 1ms

   }

}

how do i achieve this using pit driver or is there any other method.

Regards,

Anuj

[jingpan]

Hi,

Then you have to poll TFLG register. After you start PIT, you keep polling TFLG until it become 1.

You can use PIT_GetStatusFlags to read TFLG.

Regards,

Jing

[anujtanksali]

Hello,

I have used the same procedure above. I am facing an issue when multiple timer channels are configured. I am using 2 timer channels. one is configured using PIT component and other 1 is written using code as it is used for blocking delay of usec. 

Am using config tool to configure PIT component for channel 0 to generate a recurring delay of 25msec and have a ISR handler which clears the flag according to respective channel status. 

I have delay function below which uses channel 1 of PIT but channel 1 is not configured in PIT component. it is configured in below function.

void DelayUs(uint32_t usec){

// /// Set channel 1 period to usec
// PIT_SetTimerPeriod(PIT, kPIT_Chnl_1, USEC_TO_COUNT(usec,PIT_SOURCE_CLOCK));
//
// /// Enable interrupts from channel 1
// PIT_EnableInterrupts(PIT, kPIT_Chnl_1, kPIT_TimerInterruptEnable);
//
// /// Start Timer
// PIT_StartTimer(PIT, kPIT_Chnl_1);
//
//
// /// Check for interrupt flag set in ISR handler
// while(!mainObject.usecFLG){
//
// status = PIT_GetStatusFlags(PIT, kPIT_Chnl_1);
// status &= 0x01 ;
// }
//
// mainObject.usecFLG = false ;
// /// Disable interrupts from channel 1
// PIT_DisableInterrupts(PIT, kPIT_Chnl_1, kPIT_TimerInterruptEnable);
//
// /// Stop Timer
// PIT_StopTimer(PIT, kPIT_Chnl_1);

common ISR handler which clears flags as below

void PIT_IRQHandler(void)
{
volatile uint32_t status ;

status = PIT_GetStatusFlags(PIT, kPIT_Chnl_0);
if(status & kPIT_TimerFlag){
PIT_ClearStatusFlags(PIT, kPIT_Chnl_0, kPIT_TimerFlag);
mainObject.runFLG = true ;

 status = PIT_GetStatusFlags(PIT, kPIT_Chnl_1);
 if(status & kPIT_TimerFlag){
 PIT_ClearStatusFlags(PIT, kPIT_Chnl_1, kPIT_TimerFlag);
 mainObject.usecFLG = true ;
 }
}

The second channel which is configured in code by above delay function does not work in this case. the 25msec configured for channel 0 is continuously running ok and i get the status as 1 for channel 0 but not of channel 1. 

am calling the delay(100) in while loop as below

While(1){

Delay(100);

some code to make pin low

Delay(100);

some code to make pin high

}

the operation gets stuck in above highlighted line in bold while(!mainObject.usecFLG) in delay function.

if i only keep the delay function and not the 25 msec recurring timer then delay function works and status is received ok.

but if channel 0 and channel 1 are used together then delay function does not work.

please let me know what could be the issue.

Thanks

Anuj.

[jingpan]

Hi,

Sorry, I don't quite understand your meaning. Can you attach the whole code here?

Regards,

Jing