Hi, I wanted to use three channel on a single timer. The setup seems to work fine for the first two (ch1 and ch2) but not for ch3. it seems that even with HAL I have to manually set the bit TIM_CCER_CC3E on for ch3. Did I miss something?

[KRem.1]

I use these fonction to enable all three channels:

HAL_TIM_OnePulse_Start(&htim3, TIM_CHANNEL_1);

HAL_TIM_OnePulse_Start(&htim3, TIM_CHANNEL_2);

 HAL_TIM_OnePulse_Start(&htim3, TIM_CHANNEL_3);

it have to insert this to enable ch3 but just for the channel 3.

htim3.Instance->CCMR2 = TIM_CCMR2_OC3PE| (7<<TIM_CCMR2_OC3M_Pos);

 htim3.Instance->CCER |= TIM_CCER_CC3E

I'm asking this question because I'm not sure if there is an issue with HAL or it's just me.

Best regards,

[TDK]

What chip?

[KRem.1]

Stm32f103rb, the nucleo board

[TDK]

TIM_CHANNEL_3 is not a valid argument to HAL_TIM_OnePulse_Start.

https://github.com/STMicroelectronics/STM32CubeF1/blob/003dfc9e6c2e424c19a25df3934afaf7fce660d6/Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_tim.c#L2689

/**
 * @brief Starts the TIM One Pulse signal generation.
 * @param htim TIM One Pulse handle
 * @param OutputChannel TIM Channels to be enabled
 * 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
 * @retval HAL status
 */
HAL_StatusTypeDef HAL_TIM_OnePulse_Start(TIM_HandleTypeDef *htim, uint32_t OutputChannel)

Seems like it should be included, but maybe there's a reason for it being missing.

[waclawek.jan]

This function (and the related "surroundings" of it) is aimed at one particular application, where one channel serves as a hardware trigger, and the other as output.

 /* Enable the Capture compare and the Input Capture channels

   (in the OPM Mode the two possible channels that can be used are TIM_CHANNEL_1 and TIM_CHANNEL_2)

   if TIM_CHANNEL_1 is used as output, the TIM_CHANNEL_2 will be used as input and

   if TIM_CHANNEL_1 is used as input, the TIM_CHANNEL_2 will be used as output

   in all combinations, the TIM_CHANNEL_1 and TIM_CHANNEL_2 should be enabled together

   No need to enable the counter, it's enabled automatically by hardware

   (the counter starts in response to a stimulus and generate a pulse */

See also the related examples:

Configuration of TIM5 in One Pulse Mode
===================================================
 
 - The external signal is connected to TIM5_CH2 pin (PA.01), 
 and a rising edge on this input is used to trigger the Timer.
 - The One Pulse signal is output on TIM5_CH1 (PA.00).
 
 The delay value is fixed to:
 - Delay = CCR1/TIM5 counter clock 
 = 16383 / 18000000 [sec]
 
 The pulse value is fixed to : 
 - Pulse value = (TIM_Period - TIM_Pulse)/TIM5 counter clock 
 = (65535 - 16383) / 18000000 [sec]
 
 The one pulse waveform can be displayed using an oscilloscope and it looks
 like this.
 
 ____
 | |
 CH2 _________________________| |__________________________________________
 
 ___________________________
 | |
 CH1 ______________________________________| |_____
 <---Delay----><------Pulse--------------->

In other words, this is implementation of a one-shot flip-flop with delay.

This of course is only one very specific application of the OPM in timer. That's Cube/HAL for you.

Oh, and it's an excellent illustration of Cube/HAL documentation, too.

JW

[KRem.1]

ok, thank you.

I may have to adapt this function.

[KRem.1]

Hi,

I finally get my timer working as I wish. I went directly programming the register. In my case, I use the timer 1 to trigger the timer 3 (one pulse mode) on the microcontroler as i needed so extra feature from the timer 1 (the repetition counter).

Apparently, if an internal trigger is selected as the trigger input, it is not needed to configure a channel as an input.

I am a bit concern now, will I still be able to use other hal libraries on my project ?

R.

[waclawek.jan]

> will I still be able to use other hal libraries on my project ?

Probably yes, if they are not using the given timer(s). I don't use Cube/HAL.

JW