Select PA1 as TIM2 CH2, those code are copy from ST official example(TIM21), and changed to TIM2.
no output from PA1, code as below:
void ConfigureTIM2AsPWM_EdgeAligned(void)
{
/* (1) Enable the peripheral clock of Timer x */
/* (2) Enable the peripheral clock of GPIOA */
/* (3) Select alternate function mode on GPIOA pin 1 */
/* (4) Select AF2 on PA1 in AFRH for TIM2_CH2 */
RCC->APB1ENR |= RCC_APB1ENR_TIM2EN; /* (1) */
RCC->IOPENR |= RCC_IOPENR_GPIOAEN; /* (2) */
GPIOA->MODER |= 0X00000008; /* (3) */
GPIOA->AFR[0] |= 0X00000020; /* (4) */
/* (1) Set prescaler to 15, so APBCLK/16 i.e 1MHz */
/* (2) Set ARR = 8, as timer clock is 1MHz the period is 9 us */
/* (3) Set CCRx = 4, , the signal will be high during 4 us */
/* (4) Select PWM mode 1 on OC2 (OC2M = 110),
enable preload register on OC2 (OC2PE = 1) */
/* (5) Select active high polarity on OC2 (CC2P = 0, reset value),
enable the output on OC2 (CC2E = 1)*/
/* (6) Enable output (MOE = 1)*/
/* (7) Enable counter (CEN = 1)
select edge aligned mode (CMS = 00, reset value)
select direction as upcounter (DIR = 0, reset value) */
/* (8) Force update generation (UG = 1) */
TIM2->PSC = 15; /* (1) */
TIM2->ARR = 8; /* (2) */
TIM2->CCR1 = 4; /* (3) */
TIM2->CCMR1 |= TIM_CCMR1_OC2M_2 | TIM_CCMR1_OC2M_1 | TIM_CCMR1_OC2PE; /* (4) */
TIM2->CCER |= TIM_CCER_CC2E; /* (5) */
TIM2->CR1 |= TIM_CR1_CEN; /* (7) */
TIM2->EGR |= TIM_EGR_UG; /* (8) */
}
