PWM output not working?

[litus0801]

Posted on April 14, 2010 at 20:20

PWM output not working?

[yagov]

Posted on May 17, 2011 at 13:47

Hello.

I dont see the text in your program like this:  /* PWM1 Mode configuration: Channel1 */   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;   TIM_OCInitStructure.TIM_Pulse = CCR1_Val;   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

[litus0801]

Posted on May 17, 2011 at 13:47

Oh! Yes, I did not post it because a simple configuration. This is what I do:

/******************************* TIM_CONFIG

************************************

*  Configure General Purpose Timers

*  Description: We will only use Timer 2

*******************************************************************************/

static void TIM_Config(void)

{

  TIM_TimeBaseInitTypeDef  tim_config;

  TIM_OCInitTypeDef  tim_oc_config;

  /* TIM2 configuration */

  tim_config.TIM_Period = TIM2_period;          

  tim_config.TIM_Prescaler = TIM2_prescaler;       

  tim_config.TIM_ClockDivision = TIM_CKD_DIV1;    

  tim_config.TIM_CounterMode = TIM_CounterMode_Up;  

  tim_config.TIM_RepetitionCounter = 0x0000;

  TIM_TimeBaseInit(TIM2, &tim_config);

  TIM_OCStructInit(&tim_oc_config);

  /* Output Compare Timing Mode configuration: Channel1 */

  tim_oc_config.TIM_OCMode = TIM_OCMode_Timing;

  tim_oc_config.TIM_Pulse = 0x0;  

  TIM_OC1Init(TIM2, &tim_oc_config);

  /* Enable Auto Reload Register Preload */

  TIM_ARRPreloadConfig(TIM2, ENABLE);

  /* TIM2 counter enable */

  TIM_Cmd(TIM2,ENABLE);  

  /* Immediate load of TIM2 Precaler value */

  TIM_PrescalerConfig(TIM2, TIM2_prescaler, TIM_PSCReloadMode_Immediate);

  /* Clear TIM2 update pending flag */

  TIM_ClearFlag(TIM2, TIM_FLAG_Update);

  /* Enable TIM2 Update interrupt */

  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

}

/******************************* PWM_CONFIG ************************************

*  Configure PWM Timer

*  Description: We will use Timer 1 for our PWM signal generation. We'll use

*               a bits resolution defined at top of file.

*******************************************************************************/

static void PWM_Config(void)

{

  TIM_TimeBaseInitTypeDef tim_config; /* TIM1 Init Struct           */

  TIM_OCInitTypeDef       pwm_config; /* Output Compare Init Struct */

  /* Time base configuration **************************************************/

  tim_config.TIM_Prescaler = PWM_prescaler;  // Max frequency

  tim_config.TIM_CounterMode = TIM_CounterMode_Up; 

  tim_config.TIM_Period = PWM_resolution;

  tim_config.TIM_ClockDivision = TIM_CKD_DIV1;

  tim_config.TIM_RepetitionCounter = 0;

  /* Do the setup */

  TIM_TimeBaseInit(TIM1,&tim_config);

  /* Channel 1 Configuration in PWM mode **************************************/

  pwm_config.TIM_OCMode = TIM_OCMode_PWM1;

  pwm_config.TIM_OutputState = TIM_OutputState_Enable;

  pwm_config.TIM_OutputNState = TIM_OutputNState_Enable;

  /* TIM_Pulse is the duty cycle */

  pwm_config.TIM_Pulse = PWM_value;

  pwm_config.TIM_OCPolarity = TIM_OCPolarity_Low;

  pwm_config.TIM_OCNPolarity = TIM_OCNPolarity_High;

  pwm_config.TIM_OCIdleState = TIM_OCIdleState_Set;

  pwm_config.TIM_OCNIdleState = TIM_OCIdleState_Reset;

  TIM_OC1Init(TIM1,&pwm_config); // Do the setup

  /* Enable Auto Reload Register Preload */

  TIM_ARRPreloadConfig(TIM1, ENABLE);

  /* TIM1 counter enable */

  TIM_Cmd(TIM1,ENABLE);  

}

In other applications the same code worked, is that possible right?

Thanks!

[yagov]

Posted on May 17, 2011 at 13:47

At first ise that you dont use the commands for TIM1.

look here (FW lib functions for TIM1):TIM1_DeInit Resets the TIM1 peripheral registers to their default reset values. TIM1_TimeBaseInit Initializes the TIM1 Time Base Unit according to the specifiedparameters in the TIM1_TimeBaseInitStruct. TIM1_OC1Init Initializes the TIM1 Channel1 according to the specified parameters in the TIM1_OCInitStruct. TIM1_OC2Init Initializes the TIM1 Channel2 according to the specified parameters in the TIM1_OCInitStruct.

All command for timer 1 begins from TIM1

Is the problem here?

[litus0801]

Posted on May 17, 2011 at 13:47

Hi Denis!

Finally I found the solution. But it was not what you said :p Hehehe

Look, when I initialized my system I did:

1. GPIO initializing
2. RCC initializing
3. ADC, PWM initializing
4. Start converting and enable PWM output
5. TIM2 init.

Everything was ok, only initializing order were wrong. I must init RCC _before_ GPIOs. After inverting the order of this, everything worked perfect. In fact, in previous versions where I did use the same functions RCC was already initialized but I didn't know that (I was using RTOS from Micrium and when I used BSP functions the RTOS did the initialization).

Even so, thank you very much!

By the way, in my FW lib there's no functions called ''TIM1_xxx''  ?¿?¿   :S

Moderator note: should I mark this as answered?