Hello,
i am using the STM32F103C6 MCU and i would like to produce 3 different Center Aligned PWM signals with 16KHz frequency and Duty Cycle 1 to 99%. I would like to change the duty cycle on fly using the CCR registers.
I am configuring the 3 of TIM1's channels as Output Compare:
Then i choose the Center Aligned_3 mode and setting the frequency on 16KHz (frequency is correct):
Finally, every channel has the same settings as below:
With CubeMX's default code, i am just starting the OC and setting the desired pulse:
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_TIM1_Init();
/* USER CODE BEGIN 2 */
HAL_TIM_OC_Start(&htim1, TIM_CHANNEL_1);
HAL_TIM_OC_Start(&htim1, TIM_CHANNEL_2);
HAL_TIM_OC_Start(&htim1, TIM_CHANNEL_3);
TIM1->CCR1 = 400; //Channel_1 ~ 82% Duty Cycle
TIM1->CCR2 = 1125; //Channel_2 ~ 50% Duty Cycle
TIM1->CCR3 = 2200; //Channel_3 ~ 2% Duty CycleAnd on simulator everything is correct:
If we change the CCR1 to lower value:
TIM1->CCR1 = 100; //Channel_1 95% Duty CycleSeems like Channel 1 is not aligned with the others, like it is shifted:
- Can someone help me and explain me what i am doing wrong?
- Is there any other way to produce those Center Aligned PWM signals?
- What is the safest way to change duty cycle on fly? Should i use the compare IRQ?
Now i am using the "PWM Generation CHx" option but i am still facing issues with the alignment.
With the below settings:
static void MX_TIM1_Init(void)
{
/* USER CODE BEGIN TIM1_Init 0 */
/* USER CODE END TIM1_Init 0 */
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};
/* USER CODE BEGIN TIM1_Init 1 */
/* USER CODE END TIM1_Init 1 */
htim1.Instance = TIM1;
htim1.Init.Prescaler = 0;
htim1.Init.CounterMode = TIM_COUNTERMODE_CENTERALIGNED3;
htim1.Init.Period = 2250-1;
htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim1.Init.RepetitionCounter = 0;
htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
{
Error_Handler();
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = 100;
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();
}
sConfigOC.Pulse = 500;
if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
{
Error_Handler();
}
sConfigOC.Pulse = 700;
if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
{
Error_Handler();
}
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();
}
/* USER CODE BEGIN TIM1_Init 2 */
/* USER CODE END TIM1_Init 2 */
HAL_TIM_MspPostInit(&htim1);
}The output looks like this:
