Generating PWM signal and GPIO ON state from the same pin periodically.
Hello everyone,
I’m interested in electric motor drives and power electronics. I’m trying to create a C program for STM32F407 Discovery board that executes Hall sensored 6 step commutation with complementary PWM.
The program must apply a PWM signal to the high side mosfet, complement of this pwm signal to same leg low side mosfet with significant dead time and GPIO-ON State to corresponding low side mosfet according to Hall sensor state. You can see what I’m trying to do in the figure below.
I set the GPIO pins to alternate function to generate PWM and did necessary configuration to generate complement of this PWM signal. But I’m confused. For instance at sector 1, I generated both PWM signals and control the PWM3L via GPIOx->ODR register. But at sector 4 I need to apply PWM signal for the same pin(PWM3L). Do I need to configure the pin as output or alternate function? How can I configure this? Do I need to use event or interrupt. Can anyone help me please? Thanks in advance. I leave the program that impelement complementary PWM signal with 8us dead time.
void GPIO_Init(void) { RCC->AHB1ENR |= (1U<<0) | (1U<<2) ; /*GPIOA and GPIOC clock enable*/ GPIOA ->MODER |= (1U<<11); /*PA5 set as alternate func*/ GPIOA->MODER &=~ (1U<<10) ; GPIOC->MODER |= (1U<<13) ; /*PC6 set as alternate func*/ GPIOC->MODER &=~ (1U<<12) ; GPIOA->AFR[0] |= (1U<<21) ; GPIOA->AFR[0] |= (1U<<20) ; /*PA5---->AF03----TIM8_CH1N*/ GPIOA->AFR[0] &=~(1U<<19); GPIOA->AFR[0] &=~(1U<<18); GPIOC->AFR[0] |= (1U<<25); GPIOC->AFR[0] |= (1U<<24); /*PC6---->AF03----TIM8_CH1*/ GPIOC->AFR[0] &=~ (1U<<26); GPIOC->AFR[0] &=~ (1U<<27); } void PWM_Init(void) { RCC->APB2ENR |= (1U<<1); /*TIM8 clock enable*/ TIM8->PSC = 16-1; /*16 000 000 / 16 = 1 000 000 Hz = 1us period*/ TIM8->ARR =1000-1 ; /*1ms period*/ TIM8->CCR1 = 250-1; /*%25 duty*/ TIM8->CCER |= (1U<<0); TIM8->CCER |= (1U<<2); TIM8->CCER &=~ (1U<<1); /*OC1 and OC1N output polarity*/ TIM8->CCER &=~ (1U<<3); TIM8->BDTR |= (0x887F) ; /*MOE , OSSR bits and dead time calculation*/ TIM8->CCMR1 |= (1U<<6); TIM8->CCMR1 |= (1U<<5); /*PWM mode 1 */ TIM8->CCMR1 &=~ (1U<<4); TIM8->CNT = 0; /*Initialize counter*/ TIM8->CR2 |= (1U<<0); /*CCPC*/ TIM8->CR2 &=~ (1U<<8); /*output Idle of OC1 state zero*/ TIM8->CR2 |= (1U<<9) ; /*Output Idle state of OC1N*/ TIM8->CR1 |= (1U<<0); /*counter enable*/ }