Blinking Led using PIT-module

rohananand — Sun, 13 Dec 2015 13:33:05 GMT

Hello,

I am trying to blink the on-board red led using the PIT-module.The code is as follows:

#include "MKL46Z4.h"

void initPITM(void)

{

PIT_MCR= 0x00000000;//Module enable

}

void delay()

{

PIT_LDVAL0=0x00FFFFFF;//Value of timer 0

PIT_TCTRL0=0x00000001;//Timer enable

while((PIT_TFLG0 & 0x00000001)==0)

{

}

void initLEDR()

{

SIM_SCGC5=SIM_SCGC5_PORTE_MASK;

PORTE_PCR29=256;

GPIOE_PDDR=1u<<29;

}

int main(void)

{

initLEDR();

initPITM();

while(1)

{

GPIOE_PDOR=0u<<29;

delay();

GPIOE_PDOR=1u<<29;

delay();

}

return 0;

}

When I am debugging this code,it goes to PIT_MCR=0x00000000; and then goes to handler.

Please help.I am unable to find whats wrong with the code?

It goes here and then oscillates back and forth.

ldr	r0, =DefaultISR

bx r0

Re: Blinking Led using PIT-module

mjbcswitzerland — Mon, 14 Dec 2015 11:46:45 GMT

Before

PIT_MCR= 0x00000000;//Module enable

you need

SIM_SCGC6=SIM_SCGC6_PIT_MASK;

Some chips have an errate [ID7914] where there needs to be also a short delay between enabling the PIT clocks and enabling the module.

SIM_SCGC6=SIM_SCGC6_PIT_MASK;

(void)PIT_MCR; // dummy read of PIT_MCR to guaranty a minimum delay of two bus cycles after enabling the clock gate and not losing next write

PIT_MCR = 0;

Regards

Mark

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