Question
ARR update causing output glitch
Using STM32F765, I'm using tim1 with OC toggle.
The issue is glitches when I update the ARR value within the Repetition UP ISR. ARR Preload is enabled, not sure what to look at here.
D2 toggles when the TIM1_UP_TIM10_IRQHandler fires, and D3 is TIM1 CH1 output, and the glitch seems obviously caused by the SetAutoReload when it fires.
Init code
void init_stepper(void) {
ena_stepper();
LL_GPIO_InitTypeDef GPIO_InitStruct = {0};
LL_TIM_InitTypeDef TIM_InitStruct = {0};
/* USER CODE END TIM1_Init 2 */
LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_TIM1);
/**TIM1 GPIO Configuration
PA8 ------> TIM1_CH1
*/
GPIO_InitStruct.Pin = TMC_STEP_Pin;
GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_MEDIUM;
GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
GPIO_InitStruct.Alternate = LL_GPIO_AF_1;
LL_GPIO_Init(TMC_STEP_GPIO_Port, &GPIO_InitStruct);
TIM_InitStruct.Prescaler = 0;
TIM_InitStruct.CounterMode = LL_TIM_COUNTERMODE_UP;
TIM_InitStruct.Autoreload = 65535;
TIM_InitStruct.ClockDivision = LL_TIM_CLOCKDIVISION_DIV1;
TIM_InitStruct.RepetitionCounter = 0;
LL_TIM_Init(TIM1, &TIM_InitStruct);
LL_TIM_EnableARRPreload(TIM1);
LL_TIM_SetClockSource(TIM1, LL_TIM_CLOCKSOURCE_INTERNAL);
LL_TIM_DisableMasterSlaveMode(TIM1);
LL_TIM_SetPrescaler(TIM1, 63);
LL_TIM_OC_SetMode(TIM1, LL_TIM_CHANNEL_CH1, LL_TIM_OCMODE_TOGGLE);
LL_TIM_CC_EnableChannel(TIM1, LL_TIM_CHANNEL_CH1);
LL_TIM_OC_SetCompareCH1(TIM1, 0x0000);
LL_TIM_OC_SetPolarity(TIM1, LL_TIM_CHANNEL_CH1, LL_TIM_OCPOLARITY_LOW);
LL_TIM_EnableAllOutputs(TIM1);
//
NVIC_SetPriority(TIM1_UP_TIM10_IRQn, PRIORITY_TIMER1_PWM);
NVIC_EnableIRQ(TIM1_UP_TIM10_IRQn);
LL_TIM_SetRepetitionCounter(TIM1, 31);
LL_TIM_EnableIT_UPDATE(TIM1);
}
ISR
void TIM1_UP_TIM10_IRQHandler(void) {
if (LL_TIM_IsActiveFlag_UPDATE(TIM1) == 1) {
LL_GPIO_TogglePin(OUT_ALIVE_GPIO_Port, OUT_ALIVE_Pin);
LL_TIM_ClearFlag_UPDATE(TIM1);
stepTickCount += 16;
// Stop here
if (stepTickCount >= targetPosition) {
LL_TIM_DisableCounter(TIM1);
LL_TIM_SetCounter(TIM1, 0);
LL_TIM_SetAutoReload(TIM1, SystemCoreClock / 128 / 500 /* HZ */);
}
uint32_t arr = LL_TIM_GetAutoReload(TIM1);
if (!arr) {
arr = 1;
}
uint32_t currHz = 1687500 / LL_TIM_GetAutoReload(TIM1);
currHz = (currHz > 0 ? currHz : 1);
if ((targetPosition - stepTickCount) < 200) {
// Decel here
if (currHz > 750) {
currHz -= 750;
if (currHz < 750) {
currHz = 750;
}
LL_TIM_SetAutoReload(TIM1, SystemCoreClock / 128 / currHz /* HZ */);
}
} else {
// Acceleration here
if (currHz < targetSpeed) {
currHz += 750;
if (currHz > targetSpeed) {
currHz = targetSpeed;
}
LL_TIM_SetAutoReload(TIM1, SystemCoreClock / 128 / currHz /* HZ */);
}
}
}
}