#include unsigned int i = 0x12345678; unsigned char c = 2; int main(void) { RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN; GPIOB->MODER |= (1<<14*2) | (1<<7*2) | (1<<0*2); GPIOB->ODR |= (1<<14) | (1<<0); SysTick_Config(800000); while(1) { i++; } } void SysTick_Handler(void) { GPIOB->ODR ^= (1<<14) | (1<<7) | 1; }