（ARM）7/5-编程知识

（ARM）7/5

1.串口发送单个字符

2.串口发送字符串

uart4.h

#ifndef __UART4_H__
#define __UART4_H__#include "stm32mp1xx_uart.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"//初始化相关操作
void hal_uart4_init();//发送一个字符
void hal_put_char(const char str);//发送一个字符串
void hal_put_string(const char* string);//接收一个字符
char hal_get_char();//接收一个字符串
char* hal_get_string(char* arr);

uart4.c

#include "uart4.h"//初始化相关操作
void hal_uart4_init()
{//----------RCC章节初始化----------////(GPIOB,GPIOG,UART4)RCC->MP_AHB4ENSETR |= (0x1 << 1);RCC->MP_AHB4ENSETR |= (0x1 << 6);RCC->MP_APB1ENSETR |= (0x1 << 16);//---------GPIO章节初始化----------////PB2引脚设置复用功能模式GPIOB->MODER &= (~(0x3 << 4));GPIOB->MODER |= (0x2 << 4);//设置为RXGPIOB->AFRL &= (~(0xf << 8));GPIOB->AFRL |= (0x8 << 8);//PG11引脚设置复用功能模式GPIOG->MODER &= (~(0x3 << 22));GPIOG->MODER |= (0x2 << 22);//设置为TXGPIOG->AFRH &= (~(0xf << 12));GPIOG->AFRH |= (0x6 << 12);//----------UART章节初始化----------////设置串口UE = 0USART4->CR1 &= (~(0x1));//数据位宽度（1个起始位，8个数据位，n个停止位）USART4->CR1 &= (~(0x1 << 12));USART4->CR1 &= (~(0x1 << 28));//采样率（16倍）USART4->CR1 &= (~(0x1 << 15));//无奇偶校验USART4->CR1 &= (~(0x1 << 10));//接收器使能USART4->CR1 |= (0x1 << 2);//发射器使能USART4->CR1 |= (0x1 << 3);//设置1位停止位USART4->CR2 &= (~(0x3 << 12));//设置串口不分频USART4->PRESC &= (~(0xf));//设置串口波特率为115200USART4->BRR = 0x22b;//设置串口使能USART4->CR1 |= (0x1);}//发送一个字符
void hal_put_char(const char str)
{//判断发送寄存器是否为空while(!(USART4->ISR & (0x1 << 7)));//将发送的内容赋值给发送寄存器USART4->TDR = str;//判断一帧数据是否发送完成while(!(USART4->ISR & (0x1 << 6)));
}//发送一个字符串
void hal_put_string(const char* string)
{hal_put_char('\n');while(*string != '\0'){//判断发送寄存器是否为空while(!(USART4->ISR & (0x1 << 7)));//将发送的内容赋值给发送寄存器USART4->TDR = *string;string++;//判断一帧数据是否发送完成while(!(USART4->ISR & (0x1 << 6)));}hal_put_char('\r');hal_put_char('\n');
}/*
//接收一个字符
char hal_get_char()
{//判断接收数据寄存器中是否有数据while(!(USART4->ISR & (0x1 << 5)));//将接收数据寄存器中的数据读取出来char str = USART4->RDR;return str;
}
*///接收一个字符串
char* hal_get_string(char* arr)
{//循环进行接收//当键盘输入回车之后，代表字符串输出完成char *p = arr;while(1){while(!(USART4->ISR & (0x1 << 5)));*p = USART4->RDR;hal_put_char(*p);while(!(USART4->ISR & (0x1 << 6)));if(*p == '\r')break;p++;}*p = '\0';return arr;
}

main.c

#include "uart4.h"
extern void printf(const char *fmt, ...);
void delay_ms(int ms)
{int i,j;for(i = 0; i < ms;i++)for (j = 0; j < 1800; j++);
}int main()
{char arr[20] = "";hal_uart4_init();      //初始化while(1){//hal_put_char(hal_get_char()+1);      //单个字符hal_put_string(hal_get_string(arr));   //字符串}return 0;
}

实验现象