changing output compare value while code is running

[shivam1]

i am using stm32f446re. i am using timer in synchronization mode one timer triggers another timer so my query is master timers triggers slave timer to generate another timer pwm so that triggers value  i want to control so what hal function i use to control this triggers value while code is running then i want to change this trigger value.

here is an example what i want-

- lets say master generate 50% duty cycle pwm so when master is 25% of its pwm then slave gets trigger to generate its own pwm.so i want to control this 25% value. so what HAL function i use to control this value while code is running.  

[waclawek.jan · Accepted solution]

If you use Trigger mode of slave-mode controller in slave timer, that only sets TIMx_CR1.CEN, so it does nothing if TIMx_CR1.CEN is already set (i.e. if the slave timer is running continuously). If that's the case, you have to clear TIMx_CR1.CEN in slave when you change the compare value in master.

JW

[Sarra.S]

Hello @shivam1, 

check this HAL macro: 

/**
  * @brief  Sets the TIM Capture Compare Register value on runtime without
  *         calling another time ConfigChannel function.
  * @param  __HANDLE__: TIM handle.
  * @param  __CHANNEL__ : TIM Channels to be configured.
  *          This parameter can be one of the following values:
  *            @arg TIM_CHANNEL_1: TIM Channel 1 selected
  *            @arg TIM_CHANNEL_2: TIM Channel 2 selected
  *            @arg TIM_CHANNEL_3: TIM Channel 3 selected
  *            @arg TIM_CHANNEL_4: TIM Channel 4 selected
  * @param  __COMPARE__: specifies the Capture Compare register new value.
  * @retval None
  */
#define __HAL_TIM_SET_COMPARE(__HANDLE__, __CHANNEL__, __COMPARE__) \
(*(__IO uint32_t *)(&((__HANDLE__)->Instance->CCR1) + ((__CHANNEL__) >> 2)) = (__COMPARE__))

[shivam1]

thanks for your reply....

i know this function already but this not what i am asking i want to change that trigger value not width of any pwm.that function you provided is used for changing the width of pwm. i want to change that trriger value which activate second slave timer to turn on. please read my given example in my question.... 

[shivam1]

see in this photo i want to change this arrow mark value.. tell which hal macro i use to change it  

 

[waclawek.jan]

I don't use Cube/HAL.

You can look at the HAL_TIM_OC_ConfigChannel() function's source, what does it do with that value, but it probably simply stores it into TIMx_CCRx.

The macro @Sarra.S posted looks very much like it does exactly this.

In your original question, TIMx_CCRx of master provides the point, where it generates TRGO which is then input as TRGI to slave. However, as I've said, if you use Trigger mode of the Slave-mode controller of the slave timer, it sets its TIMx_CR1.CEN only once, so subsequent TRGI from master are ignored.You have to clear slave's TIMx_CR1.CEN (stop the slave counter) to have it triggered from the master (with already adjusted TIMx_CCRx which provides the moment of trigger) again.

JW