STM32H5 Comparator always trigger interrupt

[CChen.19]

Hi. I get a STM32H5 Nucleo board (MB1814) and configured comparator with neccessary settings using CubeIDE and LL library and got next generated piece of code.

int main(void)
 
{
 
 NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_3);
 
 SystemClock_Config();
 
 MX_GPIO_Init();
 
 MX_COMP1_Init();
 
 LL_COMP_Enable(COMP1);
 
 SET_BIT(COMP1->CFGR1, COMP_CFGR1_ITEN);
 
 while (1){}
 
}
 
 
 
void COMP1_IRQHandler(void)
 
{
 
 LL_EXTI_ClearRisingFlag_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_ClearFallingFlag_0_31(LL_EXTI_LINE_29);
 
SET_BIT(COMP1->ICFR, COMP_ICFR_CC1IF);
 
}
 

static void MX_COMP1_Init(void)
 
{
 
 LL_COMP_InitTypeDef COMP_InitStruct = {0};
 
 LL_GPIO_InitTypeDef GPIO_InitStruct = {0};
 
 
 
 LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_COMP);
 
 LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOA);
 
 
 
 GPIO_InitStruct.Pin = LL_GPIO_PIN_0|LL_GPIO_PIN_5;
 
 GPIO_InitStruct.Mode = LL_GPIO_MODE_ANALOG;
 
 GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
 
 LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
 
 
 NVIC_SetPriority(COMP1_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(),0, 0));
 
 NVIC_EnableIRQ(COMP1_IRQn);
 
 
 
 COMP_InitStruct.PowerMode = LL_COMP_POWERMODE_HIGHSPEED;
 
 COMP_InitStruct.InputPlus = LL_COMP_INPUT_PLUS_IO2;
 
 COMP_InitStruct.InputMinus = LL_COMP_INPUT_MINUS_IO3;
 
 COMP_InitStruct.InputHysteresis = LL_COMP_HYSTERESIS_NONE;
 
 COMP_InitStruct.OutputPolarity = LL_COMP_OUTPUTPOL_NONINVERTED;
 
 COMP_InitStruct.OutputBlankingSource = LL_COMP_BLANKINGSRC_NONE;
 
 LL_COMP_Init(COMP1, &COMP_InitStruct);
 
 
 
 __IO uint32_t wait_loop_index = 0;
 
 wait_loop_index = (LL_COMP_DELAY_VOLTAGE_SCALER_STAB_US * (SystemCoreClock / (1000000 * 2)));
 
 while(wait_loop_index != 0)
 
 {
 
  wait_loop_index--;
 
 }
 
 LL_EXTI_EnableFallingTrig_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_EnableRisingTrig_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_ClearRisingFlag_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_ClearFallingFlag_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_DisableEvent_0_31(LL_EXTI_LINE_29);
 
 LL_EXTI_EnableIT_0_31(LL_EXTI_LINE_29);
 
}

Using Power Supply

INM : 1.5V

INP : 1.8V

I can use function(LL_COMP_ReadOutputLevel(COMP1)) checking status when INM > INP or INM < INP,

but interrupts keep coming when the INP pin voltage is fixed).

[waclawek.jan · Accepted solution]

I don't use the 'H503 but from the RM it appears, that COMP has two outputs: one direct to EXTI, which in turn provides edge sensitivity; and second, a dedicated interrupt (dedicated NVIC input) through a latch in COMP itself, see RM.

So, you probably want to use the former, rather than latter.

JW