precise blocking timer in S32K3

cancel
Showing results for 
Search instead for 
Did you mean: 

precise blocking timer in S32K3

Jump to solution
220 Views
JoDo
Contributor III

Hi,

I would like to implement a precise blocking timer that can also be set for a delay of 1us. I am using the code written for the S32K1 MCU and have transferred it to the S32K3 MCU. Unfortunately it does not work properly and I measured about 389us for 1ms (expected time).

Maybe I have chosen the wrong clock source (Core_CLK) or the code is 1:1 transferable for the S32K3.

If someone has a tip for this problem or maybe a better way to implement a blocking timer, that would be great.

#define WAIT_FOR_MUL4_CYCLES(cycles) \
  __asm( \
    "movs r0, %[cycles] \n"  \
    "0: \n"                  \
      "subs r0, r0, #4 \n"   \
      "nop \n\t"             \
    "bne 0b \n"              \
     :                       \
     : [cycles] "r" (cycles) \
     : "r0", "r1", "cc"      \
  )


void BCC_MCU_WaitMs(uint16_t delay)
{
    g_sysClk = Clock_Ip_GetClockFrequency(CORE_CLK);

    uint32_t cycles = (uint32_t) g_sysClk / 1000;

    /* Advance to next multiple of 4. Value 0x04U ensures that the number
     * is not zero. */
    cycles = (cycles & 0xFFFFFFFCU) | 0x04U;

    for (; delay > 0U; delay--) {
        BCC_WAIT_FOR_MUL4_CYCLES(cycles);
    }
}
  
int main(void){
    uint8 tggGPIO = 0u;
    while(1){
        Siul2_Dio_Ip_WritePin(	GPIO_BlINKY_PORT, GPIO_BlINKY_PIN, tggGPIO);
        tggGPIO ^= 0x01;
        WaitMs(1); // approx 389us
        //WaitMs(2); // approx 760us
    }
}

 

0 Kudos
1 Solution
199 Views
danielmartynek
NXP TechSupport
NXP TechSupport

Hi @JoDo,

The S32K3 has a different core.

Why don't use Systick?

You can use the OSIF RTD driver.

 

BR, Daniel

View solution in original post

1 Reply
200 Views
danielmartynek
NXP TechSupport
NXP TechSupport

Hi @JoDo,

The S32K3 has a different core.

Why don't use Systick?

You can use the OSIF RTD driver.

 

BR, Daniel

View solution in original post