topic Storing Contents of a Register in a variable in Kinetis Microcontrollers

Storing Contents of a Register in a variable

rohananand — Wed, 30 Sep 2015 15:27:09 GMT

I am trying to store the contents of Port Data Input Register into an array data[i].

code is as follows:

#include "MKL46Z4.h" // Device header

void InitLED(void)

{

SIM->SCGC5=SIM_SCGC5_PORTD_MASK;// Enable clock to PORTD

PORTD->PCR[5]=256;// Set pin 5 of PORTD as GPIO

PTD->PDDR=(1u<<5);// Set pin 5 of PORTD as OUTPUT

}

void InitSYSTICK(void)

{

SysTick->CTRL=0;//Disable the systick timer

SysTick->LOAD=0x00FFFFFF;//Reload it to its full value 24 bits

SysTick->VAL=0;//Write something in current register to reset it

SysTick->CTRL=0x00000005;//101//1=bus clock,0= Disable interrupt,1= enable systick timer

}

int main()

{

volatile unsigned long time[50];

volatile unsigned long data[50];

unsigned long i=0,now=0,last=0,j=0;

InitLED();

InitSYSTICK();

last=SysTick->VAL;

while(1)

{

PTD->PTOR=(1u<<5);//Toggle LED

if(i<50)

{

now=SysTick->VAL;

time[i]=(last-now);

data[i]=PTD->PDIR;

last=now;

i++;

}

for(j=0;j<=800000;j++)

{}

}

When I write data[i]=PTD->PDIR; and debug, it goes to HardFault_Handler. I don't know what is the problem with this statement.Please Help?

Re: Storing Contents of a Register in a variable

mjbcswitzerland — Wed, 30 Sep 2015 16:39:59 GMT

Presumably there is something wrong with PTD->PDIR. I would step the code in disassemble mode and see which addresses are being accessed.

Other possibilities:

SIM->SCGC5=SIM_SCGC5_PORTD_MASK;// Enable clock to PORTD

looks risky.

It is OK to enable the port but if you happen to have the same style somewhere (that is not visible in what you have shown eg.

SIM->SCGC5=SIM_SCGC5_PORTC_MASK;// Enable clock to PORTC

it will be disabing the clock to Port D and then any accesses will hard fault).

The usual style is

SIM->SCGC5|=SIM_SCGC5_PORTD_MASK;// Enable clock to PORTD

Also view the Port D registers in the debugger - if any can't be accessed it will also be displayed there.

Regards

Mark

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