// 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;