NUCLEO-U575ZI unable to activate PWM pin output

[Skfir]

Hi everybody! I keep trying to out a PWM signal, using TIM1 ch1. CC do trigger fine, but the output pin doesn't change. Please help!

void TIMER_init(void){
//PA8 - CH1
	GPIOA->MODER &= ~((3 << GPIO_MODER_MODE8_Pos) + (3 << GPIO_MODER_MODE9_Pos)); //Switching off analog functionality
	GPIOA->MODER |= (2 << GPIO_MODER_MODE8_Pos) + (2 << GPIO_MODER_MODE9_Pos); //^Connect pins to the alternate function multiplexer
	GPIOA->AFR[1] &= ~(255 << GPIO_AFRH_AFSEL8_Pos); //Clearing the alternate function fields
	GPIOA->AFR[1] |= (2 << GPIO_AFRH_AFSEL8_Pos) + (1 << GPIO_AFRH_AFSEL9_Pos); //Connect timer outputs to the pins (Choosing Timer1 outputs as an alternate function)
 
	RCC->APB2ENR |= RCC_APB2ENR_TIM1EN; //Switch on the TIM1 module
	TIM1->PSC = 15; //Timer frequency is divided by 16 (PSC+1)
//Example to start the timer
	TIM1->ARR = 60535;
	TIM1->CCR1 = 32767;
	TIM1->CCMR1 |= (TIM_CCMR1_OC1M_2 + TIM_CCMR1_OC1M_1); //PWM mode 1,
	TIM1->CCER |= TIM_CCER_CC1E; //Enable Compare module CH1 output on the pin PA8
	TIM1->BDTR |= TIM_BDTR_MOE + TIM_BDTR_AOE;	 //Enable "main output" otherwise output won't work
	//**Enabling ch1 interrupt
	TIM1->DIER |= TIM_DIER_CC1IE;
	NVIC_EnableIRQ(TIM1_CC_IRQn);
	//**
	TIM1->CR1 |= TIM_CR1_CEN;	//Starting timer
}

[waclawek.jan]

Is GPIOA clock enabled in RCC?

Read out and check/post TIM and relevant GPIO registers content.

JW

[Skfir · Accepted solution]

Found the solution! The thing is the list of alternate functions starts from zero, not from one, haha. So I simply pointed at a wrong function. Now works.