Configure an PWM on a timer output.

[CDan.1]

Hi guys,

I am having a problem with the configurations for a PWM on an timer channel. I am working on a STM32L552ZE with LL library. I am tring to configure a PWM on pin PB9 (TIM17 CH1). I have first configuret as a PWM with interrupts (TIM17 update interrupt and in interrupt toggle pin) it works ok. But when I trie to configure it with OC I get nothing just the pin in 1.3V. To the pin I have connected only the base of an NPN transistor. Below you will find the code used to configure the PWM:

void Config_125kHzPWM(void)

{

   LL_TIM_InitTypeDef TIM_InitStruct={0};

   LL_TIM_OC_InitTypeDef TIM_OC_InitStruct={0};

   LL_GPIO_InitTypeDef   GPIO_InitStruct={0};

   /*Enable registers CLK*/

   RCCCLK_ENABLE_DISABLE((uint32_t *)&RCC->AHB2ENR,RCC_AHB2ENR_GPIOBEN,ENABLE);

   GPIO_InitStruct.Pin             = LL_GPIO_PIN_9;

   GPIO_InitStruct.Mode            = LL_GPIO_MODE_ALTERNATE;

   GPIO_InitStruct.Speed           = LL_GPIO_SPEED_HIGH;

   GPIO_InitStruct.Pull            = LL_GPIO_OUTPUT_PUSHPULL;

   GPIO_InitStruct.OutputType      = LL_GPIO_OUTPUT_OPENDRAIN;

   GPIO_InitStruct.Alternate       = LL_GPIO_AF_14;

   LL_GPIO_Init(GPIOB, &GPIO_InitStruct);

   RCCCLK_ENABLE_DISABLE((uint32_t *)&RCC->APB2ENR,RCC_APB2ENR_TIM17EN ,ENABLE);

   LL_TIM_SetClockSource(TIM17, LL_TIM_CLOCKSOURCE_INTERNAL);

   /* Set the default configuration */

      TIM_InitStruct.Prescaler        = (uint16_t)0x0000;

      TIM_InitStruct.CounterMode      = LL_TIM_COUNTERMODE_UP;

      TIM_InitStruct.Autoreload       = 0x00DCU;

      TIM_InitStruct.ClockDivision    = LL_TIM_CLOCKDIVISION_DIV4;

      TIM_InitStruct.RepetitionCounter = 0U;

      LL_TIM_Init(TIM17, &TIM_InitStruct);

      LL_TIM_EnableCounter(TIM17);

      //LL_TIM_EnableIT_UPDATE(TIM17);

      //LL_TIM_ClearFlag_UPDATE(TIM17);

      //NVIC_SetPriority(TIM17_IRQn, 2);

      //NVIC_EnableIRQ(TIM17_IRQn);

   /* Set the default configuration */

   TIM_OC_InitStruct.OCMode      = LL_TIM_OCMODE_PWM1;

   TIM_OC_InitStruct.OCState     = LL_TIM_OCSTATE_ENABLE;

   TIM_OC_InitStruct.OCNState    = LL_TIM_OCSTATE_ENABLE;

   TIM_OC_InitStruct.CompareValue = 0x006EU;

   TIM_OC_InitStruct.OCPolarity  = LL_TIM_OCPOLARITY_HIGH;

   TIM_OC_InitStruct.OCNPolarity = LL_TIM_OCPOLARITY_HIGH;

   TIM_OC_InitStruct.OCIdleState = LL_TIM_OCIDLESTATE_HIGH;

   TIM_OC_InitStruct.OCNIdleState = LL_TIM_OCIDLESTATE_HIGH;

   LL_TIM_OC_Init(TIM17, LL_TIM_CHANNEL_CH1, &TIM_OC_InitStruct);

   LL_TIM_OC_EnablePreload(TIM17, LL_TIM_CHANNEL_CH1);

}

And in main i just execut this function.

The MCU APB clock is 110MHz.

Can someone point me to my mistake?

Thank you.

[waclawek.jan]

Read out and check/post content of TIM and relevant GPIO registers.

JW

[CDan.1]

Here are the hex value for the registers imediatly after executing the config function:

   GPIOB

   0x00000000->AFR[0]                                                                 

   0x000000E0->AFR[1]                                                  

   0x00040100->PUPDR                                                                 

   0x00000000->OTYPER                                                                 

   0xFFFBFEBF->MODER 

   Timer17

   0x00000201->CR1                                                                 

   0x00000300->CR2                                                                 

   0x00000000->SMCR                                                                 

   0x00000000->DIER                                                                 

   0x00000003->SR                                                                 

   0x00000000->EGR                                                                

   0x00000068->CCMR1                                                                

   0x00000000->CCMR2                                                                

   0x00000005->CCER                                                               

   0x00000030->CNT                                                                

   0x00000000->PSC                                                                

   0x000000DC->ARR                                                                

   0x00000000->RCR                                                               

   0x0000006E->CCR1                                                               

   0x00000000->BDTR                                                               

   0x00000000->OR1                                                               

   0x00000000->CCMR3                                                              

   0x00000001->OR2                                                               

   0x00000000->OR3

[Mohamed Aymen HZAMI]

Hello @CDan.1​ ,

Can you please send me your code configuration ?

Thanks and Best Regards,

Mohamed Aymen.

[CDan.1]

Sry but I do not understand the question, what code do you need?

The configuration code for used to config the PWM was posted in the original post. The function is void Config_125kHzPWM(void) and it is posted.

[Mohamed Aymen HZAMI]

Hello,

You can try an example from the L5 CubeFW.

Best Regards,

Mohamed Aymen.

[waclawek.jan · Accepted solution]

Hi CDan.1,

Sorry for the late answer.

TIM17 needs to have BDTR.MOE set.

JW