LPTIM1 ISR never cleared STM32L031G6

[Quentin_27]

Hello, I would like to know if anyone has already encountered this problem.

I have an LPTIMER configured with an ARR Match interrupt at 100ms

I also want to enter my interrupt every 10ms so I added an interrupt in compare mode at 10ms.

I have 2 questions:

- When I enter my interrupt I test the interrupt that was called but both are permanently TRUE, is it possible to use the COMPARE mode interrupt with the ARR Match interrupt?

- The register allowing to clear the interrupts does not seem to work in my case, because before exiting I clear all possible interruptions through the LPTIM1->ICR register but the ISR register is still equals to 1 for all of my interrupts...  Do we have to wait several instructions before I check it ?

**INIT LPTimer 

	//--- Demarrage LSI (oscillateur interne RC 37kHz)---
	RCC->CSR |= RCC_CSR_LSION;

	//--- Selection LSI pour LPTIM ---
	RCC->CCIPR |= RCC_CCIPR_LPTIM1SEL_0;

	//--- Validation clock LPTIM ---
	RCC->APB1ENR |= RCC_APB1ENR_LPTIM1EN;

	//--- Conf LPTIM
	LPTIM1->CFGR |= LPTIM_CFGR_PRESC_2; //-- Prescaler = 100b = /16 => 37000/16 = 2312,5Hz
	LPTIM1->IER |= LPTIM_IER_ARRMIE;
	LPTIM1->IER |= LPTIM_IER_CMPMIE;

	LPTIM1->CR |= LPTIM_CR_ENABLE; 		//-- Enable LPTimer

	LPTIM1->ARR = 232;	// T = (1 / 2312,5Hz) x 232 = 100ms
	LPTIM1->CMP = 22;

	LPTIM1->CR |= LPTIM_CR_CNTSTRT; 		


	//--- All interrupt configured to ON
	NVIC_EnableIRQ(LPTIM1_IRQn);

*INTERRUPT

//-----------------------------------------------------------------------------
void LPTIM1_IRQHandler(void)
//-----------------------------------------------------------------------------
{

	if((LPTIM1->ISR & LPTIM_ISR_CMPM))
	{
		lpTim.uptime_cmp++;
	}
	if (LPTIM1->ISR & LPTIM_ISR_ARRM)
	{
                //DEBUG
		LED_ORANGE_ON;
		Delay10usASM();
		LED_ORANGE_OFF;
                //--DEBUG

		lpTim.flag = TRUE;
		lpTim.uptime++;
	}
	LPTIM1->ICR = 0x0000007F;		//--- Clear all Flag
}

Thanks.

[gbm · Accepted solution]

Your compare interrupt fires 10 ms after every ARR interrupt, once per reload period, not every 10 ms. If you check it with the debugger, both flags are set, cause you stop the program while the timer is running and generating interrupts.