STM32F429 PWM with Timer 2

[Daattavya Aggarwal]

Posted on August 02, 2017 at 19:41

I am using STM32F429 discovery board.

I am trying to generate pwm output on pin 11 of GPIO G. I have set and enabled the corresponding registers and bits but there is no output on pin 11. If I write a simple delay code then pin 11 does go high and the code works fine. I am coding using direct registers. Any suggestions?

&sharpinclude <stm32f4xx.h>

void clk_sys()

{

RCC ->CFGR |= RCC_CFGR_MCO1_0;

RCC ->CFGR |= RCC_CFGR_MCO1_1;

RCC ->CR |= RCC_CR_PLLON;

RCC ->APB1ENR |= RCC_APB1ENR_TIM2EN;

}

void enable_gpio()//setting pin 11 of port g for AF1 which corresponds to timer 2.

{

RCC ->AHB1ENR |= RCC_AHB1ENR_GPIOGEN; //Enables port G input output pins by setting the corresponding bit in advanced high performance bus 1 register.

GPIOG ->MODER |= GPIO_MODER_MODER11_1; //Configures pin 11 for alternate function mode by setting the corresponding bit in the mode register

GPIOG ->OTYPER &= ~(GPIO_OTYPER_OT_11); //Makes the output type as push-pull by resetting the corresponding bit in output type register.

GPIOG ->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR11_1;//Makes the output high speed.

GPIOG ->PUPDR &= ~(GPIO_PUPDR_PUPDR11);//No pull up or pull down.

GPIOG ->AFR[1] |= GPIO_AF1_TIM2;

}

void generate_pwm()

{

TIM2 ->CCMR1 |= TIM_CCMR1_OC1M_2;

TIM2 ->CCMR1 |= TIM_CCMR1_OC1M_1;

TIM2 ->CCMR1 &= ~(TIM_CCMR1_OC1M_0);

TIM2 ->CCMR1 |= TIM_CCMR1_OC1PE;

TIM2 ->CR1 |= TIM_CR1_ARPE;

TIM2 ->EGR |= TIM_EGR_UG;

TIM2 ->CCER |= TIM_CCER_CC1P;

TIM2 ->CCER |= TIM_CCER_CC1E;

TIM2 ->ARR = 0xFFF;

TIM2 ->CCR1 = 0xFF;

TIM2 ->CR1 |= TIM_CR1_CEN;

HAL_TIM_PWM_Start;

while(TIM2 ->CNT < TIM2 ->CCR1)

{

GPIOG ->BSRRL |= GPIO_BSRR_BS_11;

}

}

int main(void)

{

clk_sys();

enable_gpio();

while(1)

{

generate_pwm();

// GPIOG ->BSRRL |= GPIO_BSRR_BS_11;

}

}

#pwm #stm32f

[waclawek.jan]

Posted on August 02, 2017 at 22:48

You can't assign functions to pins randomly. PG11 does not connect to TIM2_CH1 - for that you'd need PA0, PA5 or PA15. Look at the table in the STM32F429's datasheet:

etc.

GPIOG ->AFR[1] |= GPIO_AF1_TIM2;

This is probably wrong too. I don't know where do you have GPIO_AF1_TIM2 from, but most likely it's value is 1 and you'd need to shift it to left to match the pin's respective position in AFR[].

HAL_TIM_PWM_Start;

This is almost certainly not what you wanted. If you want to call a function, you must add the brackets, HAL_TIM_PWM_Start().

JW

[Daattavya Aggarwal]

Posted on August 03, 2017 at 15:11

 ,

 ,

Thank you so much! I made the suggested changes. I had already found my mistake in taking pin G-11 and had replaced it with pin A5 already but all other suggestions helped a lot. The code is working fine now and I am getting desired output. For anyone who is having this problem, here is my updated code

♯ include <,stm32f4xx.h>,

 ,

void clk_sys()

 ,

{

 ,

RCC ->,CFGR |= RCC_CFGR_MCO1_0,

 ,

RCC ->,CFGR |= RCC_CFGR_MCO1_1,

 ,

RCC ->,CR |= RCC_CR_PLLON,

 ,

RCC ->,APB1ENR |= RCC_APB1ENR_TIM2EN,

 ,

}

 ,

void enable_gpio()//setting pin 11 of port g for AF1 which corresponds to timer 2.

 ,

{

 ,

RCC ->,AHB1ENR |= RCC_AHB1ENR_GPIOAEN, //Enables port G input output pins by setting the corresponding bit in advanced high performance bus 1 register.

 ,

GPIOA ->,MODER |= GPIO_MODER_MODER5_1, //Configures pin 9 for alternate function mode by setting the corresponding bit in the mode register

 ,

GPIOA ->,OTYPER &,= ~(GPIO_OTYPER_OT_5), //Makes the output type as push-pull by resetting the corresponding bit in output type register.

 ,

GPIOA ->,OSPEEDR |= GPIO_OSPEEDER_OSPEEDR5_1,//Makes the output high speed.

 ,

GPIOA ->,PUPDR &,= ~(GPIO_PUPDR_PUPDR5),//No pull up or pull down.

 ,

GPIOA ->,AFR[0] = GPIO_AF1_TIM2<,<,20,

 ,

}

 ,

void generate_pwm()

 ,

{

TIM2 ->,CCMR1 |= TIM_CCMR1_OC1M_2,

 ,

TIM2 ->,CCMR1 |= TIM_CCMR1_OC1M_1,

 ,

TIM2 ->,CCMR1 &,= ~(TIM_CCMR1_OC1M_0),

 ,

TIM2 ->,CCMR1 |= TIM_CCMR1_OC1PE,

 ,

TIM2 ->,CR1 |= TIM_CR1_ARPE,

 ,

TIM2 ->,EGR |= TIM_EGR_UG,

 ,

TIM2 ->,CCER |= TIM_CCER_CC1P,

 ,

TIM2 ->,CCER |= TIM_CCER_CC1E,

 ,

TIM2 ->,ARR = 0x08,

 ,

TIM2 ->,CCR1 = 0x06,

 ,

TIM2 ->,CR1 |= TIM_CR1_CEN,

while(TIM2 ->,CNT <, TIM2 ->,CCR1)

 ,

{

 ,

GPIOA ->,BSRRL |= GPIO_BSRR_BS_5,

 ,

}

 ,

}

 ,

int main(void)

 ,

{

 ,

clk_sys(),

 ,

enable_gpio(),

 ,

while(1)

 ,

{

 ,

generate_pwm(),

 ,

// GPIOE ->,BSRRL |= GPIO_BSRR_BS_9,

 ,

}

 ,

}