Periodic interrupt from LPTMR, using NXP S32K14x, S32DS for ARM and RTM SDK

[Joao_Roscoe]

I'm trying to use LPTMR to create a 1ms periodic interrupt for a bare metal simple scheduler. I'm programming for NXP's S32K144 using S32DS for ARM, with the S32K14x RTM SDK for GCC, version 2.0.0 (not the beta).

I have already added the LPTMR component to my project, and used component inspector to adjust a timer configuration to suit. Right now, the config is as below:

Code:

-------------------

const lptmr_config_t lpTmr1_config0 = {
.workMode = LPTMR_WORKMODE_TIMER,
.dmaRequest = false,
.interruptEnable = true,
.freeRun = false,
.compareValue = 1000U,
.counterUnits = LPTMR_COUNTER_UNITS_MICROSECONDS,
.clockSelect = LPTMR_CLOCKSOURCE_RTC,
.prescaler = LPTMR_PRESCALE_4_GLITCHFILTER_2,
.bypassPrescaler = false,
.pinSelect = LPTMR_PINSELECT_TRGMUX,
.pinPolarity = LPTMR_PINPOLARITY_RISING,
};

-------------------

Also, I have created a custom LPTMR0_IRQHandler() function;

And I have added some timer setup code to main():

Code:

-------------------

LPTMR_DRV_Init(INST_LPTMR1, &lpTmr1_config0, TRUE);

LPTMR_DRV_SetInterrupt(INST_LPTMR1, TRUE);

-------------------

However, while debugging, it seems that the interrupt handler is never executed.

What am I missing here?

Also, do I need to clear anything in LPTMR registers before leaving the ISR?

Best regards,

Joao

[danielmartynek]

Hi Joao,

There is an SDK example that shows how to use it.

Have you enabled the interrupt in the NVIC registers using:

Yes, you need to clear the CSR_TCF flag.

Regards,

Daniel

[Joao_Roscoe]

Right on the spot!

Both the interrupt enable at setup and the compare flag clearing, in the interrupt handler, were missing. Added them, and now I have a minimalistic baremetal scheduler running.

I'm using the interrupt vectors already in place on flash, so the INT_SYS_InstallHandler part was not needed.

Really nice, thank you for your time and attention.

Best regards,

Joao