I have a STM32F429 Discovery and wants set a PWM to toggle led with period of 1 second using Timer 1, channel 1.
So, I follow this equation:
My clock APB1 is set to 1MHz.
So by my calculations I got a value for the Prescaler = 19.
PWM_Frequency = 1Hz;
Timer_Clock = 1MHz;
Timer_Count = 49999;
RCR = 0;
And for the pulse 50% I use:
pulse_length = ((TIM_Period + 1) * DutyCycle) / 100 - 1;
pulse_lenght = 24999;
But not works, the Led blinks very faster.
Follow my code:
static void MX_TIM1_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig;
TIM_MasterConfigTypeDef sMasterConfig;
TIM_OC_InitTypeDef sConfigOC;
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig;
htim1.Instance = TIM1;
htim1.Init.Prescaler = 19;
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Period = 49999;
htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim1.Init.RepetitionCounter = 0;
if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = 24999;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
sBreakDeadTimeConfig.DeadTime = 0;
sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
HAL_TIM_MspPostInit(&htim1);
}