Controlling Rgb led using Timers in stm32

[rubenles]

Hi, i am using Timers to control the intensity of a RGB LED. I need help with a code because I don't know why i have to do this thing.

I have these lines:

TIM1->CCR1 = Intensity; For Red Color

TIM1->CCR2 = Intensity; For green color

TIM1->CCR4 = Intensity; For blue color

but it doesn't work while calling 

(&htim1, TIM_CHANNEL_4);

But if i do this:

// Set alternate output for CH2, disabling main output (no need of it because already disabled, but just in case)

CLEAR_BIT(TIM1->CCER, 1 << 4);

SET_BIT(TIM1->CCER, 1 << 6);

// Set alternate output for CH1, disabling main output (no need of last thing but whatever)

CLEAR_BIT(TIM1->CCER, 1 << 0);

SET_BIT(TIM1->CCER, 1 << 2);

HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_4);

It starts working. This last code is not mine, this is why i am asking this. Why i have to use clear bit, and do this shifts? I have no idea with this. 

Thank you so much.

[GwenoleB]

Hello @rubenles,

---

TIM1->CCR1 = Intensity; For Red Color

TIM1->CCR2 = Intensity; For green color

TIM1->CCR4 = Intensity; For blue color

---

I guess those lines are used during TIMER configuration. It allows to select the pulse width for each channel.

Could you share your configuration function? Could you also that channels 1 & 2 are already setup before starting channel 4?

Best Regards,

Gwénolé

[rubenles]

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(timHandle->Instance==TIM1)
  {
  /* USER CODE BEGIN TIM1_MspPostInit 0 */

  /* USER CODE END TIM1_MspPostInit 0 */
    __HAL_RCC_GPIOE_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**TIM1 GPIO Configuration
    PE8     ------> TIM1_CH1N
    PE10     ------> TIM1_CH2N
    PA11     ------> TIM1_CH4
    */
    GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_10;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
    HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = GPIO_PIN_11;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

My doubt is why to do CCER, 1 << 4, CCER, 1 << 6, and those lines.., the configuration i think it's ok.

[GwenoleB · Accepted solution]

Hello,

Based on GPIO configuration, it seems you are using CH1N, CH2N and CH4 channels of TIM1. Therefore, CH1 and CH2 didn't need to be enabled. However, CCER, 1 << 4, CCER, 1 << 6 are used to disable CH2 channel and enable CH2N which normally not required.

You should have the following startup sequence:

HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_4);
HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_1);
HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_2);

Is working well on my side.

Best Regards,

Gwénolé

[rubenles]

I tried to do what you said deleting my shift lines and it works but not perfectly... 

When i use TIM1->CCR2 = 500; it switches on the green color that is right, when i use TIM1->CCR4 = 500; blue color switches on, but, when i use  TIM1->CCR1 = 500; it has to switch on to red color but the result is an strange green.

Using the code i sent before, using CCR1 shows red color, and now it hasn't. What it could be?

Thank you so much, i think i am near the final solution!!

[rubenles]

@GwenoleB Fixed, i have other line of CCR2 in other place of the code, i was crazy looking for the error. The thing you tell me works perfectly!! Thank you so much