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PWM on TIM4 - STM32F205

Question asked by dupont.michael on Apr 29, 2014
Latest reply on Apr 29, 2014 by dupont.michael
Greetings,
I have a project running with the STM32F205RCT6 and currently have PWM running according to the following configurations:
TIM1 -- Channel 1 - GPIOA-8
TIM1 -- Channel 2 - GPIOA-9
TIM1 -- Channel 3 - GPIOA-10
TIM3 -- Channel 1 - GPIOA - 6
TIM3 -- Channel 2 - GPIOA - 7

My application requires 2 additional PWM channels in conjunction with the ones above and I am not able to get the following to work:
TIM4 -- Channel 1 - GPIOB - 14
TIM4 -- Channel 2 - GPIOB - 8

The timer appears to be running but the output pin does not appear to be properly mapped to the timer output.

Here's the code I'm using to setup TIM4:


static void TIM_Config(void)
{
    GPIO_InitTypeDef            GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef     TIM_TimeBaseStructure;
    TIM_OCInitTypeDef           TIM_OCInitStructure;
    uint16_t preloadValue = 0;
 
    /* TIM4 clock enable */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
 
    /* GPIOB clock enable */
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
 
    /* GPIOB Configuration: TIM4 CH1 (PB14)  CH2 (PB8) */
    GPIO_StructInit(&GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Pin     = GPIO_Pin_14 | GPIO_Pin_8;
    GPIO_InitStructure.GPIO_Mode    = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed   = GPIO_Speed_100MHz;
    GPIO_InitStructure.GPIO_OType   = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd    = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
 
     
    /* Connect TIM4 pins to AF */ 
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource8,    GPIO_AF_TIM4);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource14,   GPIO_AF_TIM4);
 
    /* Compute the prescaler value */
    preloadValue = (uint16_t) ((SystemCoreClock /2) / 32000) - 1;
 
    /* Time base configuration */
    TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
    TIM_TimeBaseStructure.TIM_Period = preloadValue;
    TIM_TimeBaseStructure.TIM_Prescaler =  0;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
 
    TIM_ARRPreloadConfig(TIM4, ENABLE);
 
    /* PWM1 Mode configuration: Channel1 */
    TIM_OCStructInit(&TIM_OCInitStructure);
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 100; // Constant plugged in just for testing
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM4, &TIM_OCInitStructure);
    TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);
 
    /* PWM1 Mode configuration: Channel2 */
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 100; // Constant plugged in just for testing
    TIM_OC2Init(TIM4, &TIM_OCInitStructure);
    TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);
 
    /* TIM4 enable counter */
    TIM_Cmd(TIM4, ENABLE);
}

I have tried using other timers (with the exception of TIM8) to no avail.

I appreciate any insight.
Thanks in advance,
Michael A. Dupont

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