callback not getting triggered by 1us timer (TIM5)

[debug]

HI,

I set TIM5 up to trigger every 1us (APB1 42MHz) with the below function and I expect HAL_TIM_PeriodElapsedCallback() to be invoked every 1us but that's not the case. How do I make sure that the callback gets invoked properly?

My init function:

static void manual_TIM5_Init(void)

{

 __HAL_RCC_TIM5_CLK_ENABLE(); // start the Timer5 clock




TIM_ClockConfigTypeDef sClockSourceConfig = {0};

TIM_MasterConfigTypeDef sMasterConfig = {0};

 htim5.Instance = TIM5;

 htim5.Init.Prescaler = 1;

 htim5.Init.CounterMode = TIM_COUNTERMODE_UP;

 htim5.Init.Period = 20;

 htim5.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;

 htim5.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;

if (HAL_TIM_Base_Init(&htim5) != HAL_OK)

{

Error_Handler();

}

sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;

if (HAL_TIM_ConfigClockSource(&htim5, &sClockSourceConfig) != HAL_OK)

{

Error_Handler();

}

sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;

sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;

if (HAL_TIMEx_MasterConfigSynchronization(&htim5, &sMasterConfig) != HAL_OK)

{

Error_Handler();

}

}

[debug]

I missed to mention that it does get started with:

HAL_TIM_Base_Start_IT(&htim5);

[AScha.3 · Accepted solution]

Hi,

seems same "problem" ... 🙂

see:

https://community.st.com/t5/stm32-mcus-products/stm32g474re-general-purpose-timer-tim16/m-p/669419#M242931

>How do I make sure that the callback gets invoked properly?

Make it 100x slower...

[Tesla DeLorean]

Prescaler and Period as set as N-1

So 20 is DIV21

Interrupting at 1us / 1MHz is impractical, even without the excess baggage of HAL with it's call-ins and call-backs. The processor will saturate with not productive work.

Use a maximal TIM clocking the CNT at 1 MHz, such that you can count off elapsed time.

Clocking fast will improve your ability to resolve

[debug]

Yes for a work around, I have timer every 1 second and it just gets the microsecond timer value TIM5->CNT.