hey,
I wrote below code but I never get 'A' in output!!!!
I use Arduino uno to read data!
void SysTick_Handler(void){ i++; if(i==1000) i=0; } int main(){ RCC->AHB1ENR|=RCC_AHB1ENR_GPIOAEN; RCC->APB1ENR |=RCC_APB1ENR_USART2EN; // enable usart2 //PA2,PA3 GPIOA->MODER |=0xA0; // enable PA2,PA3 GPIOA->OSPEEDR |=0xA0; // set speed GPIOA->AFR[0]=0x7700; // set AFR7 USART2->CR1=0x2008; USART2->BRR=0x1117; SysTick_Config(168000); while(1){ USART2->DR='A'; } }