// Configure PA6 & PA7 as Alternate function GPIOA->MODER &= ~(GPIO_MODER_MODE6 | GPIO_MODER_MODE7); GPIOA->MODER |= GPIO_MODER_MODE6_1 | GPIO_MODER_MODE7_1; // Configure PB0 & PB1 as Alternate function GPIOB->MODER &= ~(GPIO_MODER_MODE0 | GPIO_MODER_MODE1); GPIOB->MODER |= GPIO_MODER_MODE0_1 | GPIO_MODER_MODE1_1;