uart.c

#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_uart.h"
// UART4_TX : PG11  AF6
// UART4_RX : PB2   AF8
void __uart_init()
{// GPIOB2 设置为复用功能GPIOB->MODER &= (~(0x3 << 4));GPIOB->MODER |= (0x2 << 4);GPIOB->AFRL &= (~(0xF << 8));GPIOB->AFRL |= (0x8 << 8);// GPIOG11 设置为复用功能 GPIOG->MODER &= (~(0x3 << 22));GPIOG->MODER |= (0x2 << 4);GPIOG->AFRH &= (~(0xF << 12));GPIOG->AFRH |= (0x6 << 12);// 设置数据长度为8位   USART_CR1  USART4->CR1 &= (~(0x1 << 28));USART4->CR1 &= (~(0x1 << 12));// 采样率为16位 USART4->CR1 &= (~(0x1 << 15));// 设置波特率为115200bps USART4->PRESC &= (~(0xF << 0));USART4->BRR = 0xD0;// 停止位1位USART4->CR2 &= (~(0x3 << 12));// 使能USART串口 USART4->CR1 |= (0x1 << 0);// 使能USART的发送或者接收功能 USART4->CR1 |= (0x1 << 3);USART4->CR1 |= (0x1 << 2);}void __uart_putc(const char data)
{while (!(USART4->ISR & (0x1 << 7)));USART4->TDR = data;if (data == '\n')__uart_putc('\r');
}
void __uart_puts(const  char  *pstr)
{while(*pstr != '\0')__uart_putc(*pstr++);
}char __uart_getc(void)
{char ch;while(!(USART4->ISR & (0x1 << 5)));ch = (char)USART4->RDR;return ch;
}

uart.h

#ifndef __UART_H__
#define __UART_H__void __uart_init();void __uart_putc(const char data);void __uart_puts(const  char  *pstr);char __uart_getc(void);#endif

mian,c

main()
{//1.串口的初始化__uart_init();char r,t;while(1){//2.接收一个字节数据r = __uart_getc();printf("%c\n",r);//3/发送一个字节数据printf("请输入：\n");scanf("%c",&t);__uart_putc(t);}
}