STM32F103C(Bluepill) Tx:#include "stm32f103x6.h"#define USART2CLKEN (0x01UL << 17U)#define SYS_FREQ 72000000#define APB1_CLK 36000000#define UART_BAUDRATE 9600void uart2_write(int ch);void uart2_tx_init(void);int main(void){ uart2_tx_init(); while(1)...