STM32L4 Complementary PWM use only the negative Channel

Question

I have problems using the complementary PWM feature of the STM32-L432KC. The non-complemementary pin ch1 is generating the right signal, but the ch1n pin is always at GND.

I want to use channel 1,2 and 3 on Timer 1, optimally only the inverse channel, as far as i can see this should be possible. For testing is have also enabled the ch1 which is working.

I have configured the HAL using CubeMx, my initialisation code is:

void MX_TIM1_Init(void)
{

  TIM_MasterConfigTypeDef sMasterConfig;
  TIM_OC_InitTypeDef sConfigOC;
  TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig;

  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 80;
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 20000;
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.RepetitionCounter = 0;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_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 = 1000;
  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__);
  }

  if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_3) != 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.BreakFilter = 0;
  sBreakDeadTimeConfig.Break2State = TIM_BREAK2_DISABLE;
  sBreakDeadTimeConfig.Break2Polarity = TIM_BREAK2POLARITY_HIGH;
  sBreakDeadTimeConfig.Break2Filter = 0;
  sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
  if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  HAL_TIM_MspPostInit(&htim1);

}

Is there anything configured incorrectly? Is it possible to only use the inverse channel?

I start the timer by calling:

HAL_TIM_Base_Start(&htim1);
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_2);
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_3);

Answer 1

you haven't started the NChannels. do it like this:

   HAL_TIM_MspPostInit(&htim1);


   /* Start channels x*/

   if(HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_3) != HAL_OK)
   {
     /* Starting Error*/
     Error_Handler();
   }
   /* Start channel xN*/
   if(HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_3) != HAL_OK)
   {
    /*Starting Error*/
     Error_Handler();
   }

   if(HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_2) != HAL_OK)
   {
     /* Starting Error*/
     Error_Handler();
   }
   /* Start channel xN*/
   if(HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_2) != HAL_OK)
   {
    /*Starting Error*/
     Error_Handler();
   }

   if(HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1) != HAL_OK)
   {
     /* Starting Error*/
     Error_Handler();
   }
   /* Start channel xN*/
   if(HAL_TIMEx_PWMN_Start(&htim1, TIM_CHANNEL_1) != HAL_OK)
   {
    /*Starting Error*/
     Error_Handler();
   }

Answer 2

When you call HAL_TIM_PWM_Init function it calls HAL_TIM_PWM_MspInit that commonly placed in stm32...._hal_msp.c in project sources. There is initialization of GPIO for working timers peripheral. Something like this

  GPIO_InitStruct.Pin = TIM_LED_GPIO_PIN_CHANNEL1;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_PULLDOWN;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = TIM_LED_GPIO_AF;
  HAL_GPIO_Init(TIM_LED_GPIO_CHANNEL1_PORT, &GPIO_InitStruct);

So possibly you have no init there?