STM32F303VC Timer1 Complementary PWM Doesnt work

Question

I use Timer 1 for creating Complimentary PWM Output. I Set all registers according to the STM32F3 Reference Manual. When i debug code, The Timer Counter counts very well but the TIM1_CH1 Output doesnt output anything.(Other Channel Outputs have the same issue)

Here is my code :

void Timer1_PWMInit()
{
//----------------Setup Timer 1 for 25khz Center Aligned PWM-----------------
    RCC->APB2ENR |= RCC_APB2ENR_TIM1EN; // Enable Timer 1 Clock
    GPIOE->AFR[1] |= 0x20; // Set Alternate Function 2 For Timer 1 CH1 Output

    TIM1->CR1 = 0; // Clear CR1 Register(Turn off Timer 1)

    TIM1->CNT = 0; // Clear Timer Counter
    TIM1->PSC = 0; // Set Timer 1 Prescaler to 1:1
    TIM1->ARR = 320; // 40 us(25 khz) PWM Period
    TIM1->CCR1 = 320; // Timer 1 Channel 1 Duty Cycle(%50)
    TIM1->CCR2 = 320; // Timer 1 Channel 2 Duty Cycle(%50)
    TIM1->CCR3 = 320; // Timer 1 Channel 3 Duty Cycle(%50)
    TIM1->CCR5 = 0; // Timer 1 Channel 5 Duty Cycle

    TIM1->CCMR1 = 0x6868; // Set Channel 1 and Channel 2 Output Compare mode to PWM Mode
    TIM1->CCMR2 = 0x68; // Set Channel 3 Output Compare mode to PWM Mode
    TIM1->CCMR3 = 0x10048; // Set Channel 5 Output Compare Mode to Combined PWM Mode
    TIM1->CCER = 0x10555; // Enable Output Compare Channels

    TIM1->CR1 = 0xE0; // Set Counting Mode to Center Aligned Mode
    TIM1->EGR |= 0x1; // Set UG bit for Updating Registers
    TIM1->BDTR = 0xC800; // Set MOE and OOSR bits for enabling Output
    TIM1->CR1 |= 0x1; // Enable Timer 1

    //-------------------------------------------------------------------------
}

First, don't use magic numbers. Instead, use pre-defined bit names. Most people (including me) won't bother writing your magic numbers into a calculator and then checking them from manual by counting/tracking each of them. Second, define "It doesn't work." What is the expected behavior? What is your observation? What happens when you run the code? — Tagli
@Tagli In Embedded it sometimes does not make sense, expecially for prototype code (which should be at least carfully reviewed later, better not used at all, of course). And for integer values, it depends. But yeah, there could have been at least some constant macros used. — too honest for this site

recep recep · Accepted Answer · 2021-03-12T05:42:07

Try to enable GPIOE clock using 'RCC_AHBENR_GPIOEEN' and also set alternate function for the other timer channel output pins.

STM32F303VC Timer1 Complementary PWM Doesnt work

1 Answers