2024-07-15 08:37 AM
Hello
I am working with an STM32G474RET6, using Timer 3 in one-pulse mode with an external trigger.
Below is my Timer 3 initialization code:
static void MX_TIM3_Init(void)
{
/* USER CODE BEGIN TIM3_Init 0 */
/* USER CODE END TIM3_Init 0 */
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_SlaveConfigTypeDef sSlaveConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
/* USER CODE BEGIN TIM3_Init 1 */
/* USER CODE END TIM3_Init 1 */
htim3.Instance = TIM3;
htim3.Init.Prescaler = 0;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 4097;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV4;
htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
Error_Handler();
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_OnePulse_Init(&htim3, TIM_OPMODE_SINGLE) != HAL_OK)
{
Error_Handler();
}
sSlaveConfig.SlaveMode = TIM_SLAVEMODE_COMBINED_RESETTRIGGER;
sSlaveConfig.InputTrigger = TIM_TS_ETRF;
sSlaveConfig.TriggerPolarity = TIM_TRIGGERPOLARITY_NONINVERTED;
sSlaveConfig.TriggerPrescaler = TIM_TRIGGERPRESCALER_DIV1;
sSlaveConfig.TriggerFilter = 0xf;
if (HAL_TIM_SlaveConfigSynchro(&htim3, &sSlaveConfig) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_PWM2;
sConfigOC.Pulse = 1;
sConfigOC.OCPolarity = TIM_OCPOLARITY_LOW;
sConfigOC.OCFastMode = TIM_OCFAST_ENABLE;
if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_4) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM3_Init 2 */
/* USER CODE END TIM3_Init 2 */
HAL_TIM_MspPostInit(&htim3);
}
I am facing an issue in one of our systems where I suspect a very noisy trigger signal. The MCU receives a 1500 µs width positive trigger, and Timer 3 should be triggered on the rising edge.
Timer 3 clock is 64 MHz, and I have set the filter value: ETF = 0xF, which corresponds to a debounce filter value of 14µs-16µs. However, I discovered that the trigger is not detected with this setting and had to reduce the filter value below ETF = 5 to get it working.
Unfortunately, I cannot observe the actual trigger behavior with an oscilloscope because this system is installed thousands of kilometers away in Australia.
I would like to understand the trigger detection behavior of the MCU in this scenario. Specifically:
Here is some additional context:
Any insights or suggestions on how to handle this situation better would be greatly appreciated.
Thank you.
Alex