8.18 作业

STM32MP1xxUART4驱动初始化及串口通信函数实现

原创于 2023-08-18 18:46:56 发布 · 215 阅读

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文章详细描述了STM32MP1xx平台上的UART4串口通信初始化过程，包括GPIO配置、波特率设置以及put_string、put_char、get_string和charge_char等串口操作函数的实现。

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()
{
	while(1)
	{
		//put_char(get_char()+1);
		put_string(get_string());
	}
	return 0;
}

uart4.h

#ifndef __UART4_H__
#define __UART4_H__

#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_uart.h"

void uart4_init();
void put_string(const char *buf);
void put_char(const char buf);
char* get_string();
char get_char();

#endif

uart4.c

#include "uart4.h"

void uart4_init()
{
	//rcc初始化
	//使能gpiob
	RCC->MP_AHB4ENSETR |= (0x1<<1);
	//使能gpiog
	RCC->MP_AHB4ENSETR |= (0x1<<6);	
	//使能uart4
	RCC->MP_APB1ENSETR |= (0x1<<16);
	//gpio初始化
	//设置pb2
	GPIOB->MODER &= (~(0x3)<<4);
	GPIOB->MODER |= (0x2<<4);

	GPIOB->OTYPER &= (~(0X1<<2));

	GPIOB->OSPEEDR &= (~(0X3<<4));

	GPIOB->PUPDR &= (~(0X3<<4));

	GPIOB->AFRL &= (~(0XF<<8));
	GPIOB->AFRL |= (0X8<<8);
	//设置pg11
	GPIOG->MODER &= (~(0x3)<<22);
	GPIOG->MODER |= (0x2<<22);

	GPIOG->OTYPER &= (~(0X1<<11));

	GPIOG->OSPEEDR &= (~(0X3<<22));

	GPIOG->PUPDR &= (~(0X3<<22));

	GPIOG->AFRH &= (~(0XF<<12));
	GPIOG->AFRH |= (0X6<<12);
	//uart4初始化
	//设置cr1 ue位不使能
	USART4->CR1 |= ~0X1;
	//WORD LENGTH
	USART4->CR1 &= (~(0X1<<12));
	USART4->CR1 &= (~(0X1<<28));
	//设置16倍采样
	USART4->CR1 &= (~(0X1<<15));
	//不分频
	USART4->PRESC &= (~0XF); 
	//设置波特率
	USART4->BRR &= (~0XFFFF);
	USART4->BRR |= 0X22B;
	//设置cr2停止位
	USART4->CR2 &= (~(0X3<<12));
	//设置无校验
	USART4->CR1 &= (~(0X1<<10));
	//设置cr1 ue位使能
	USART4->CR1 |= 0X1;
	//设置cr1 te位使能
	USART4->CR1 |= ~(0X1<<3);
	//设置cr1 re位使能
	USART4->CR1 |= ~(0X1<<2);
}

void put_string(const char *buf)
{
	for(int i=0;buf[i]!=0;i++)
	{
		put_char(buf[i]);
	}
}
void put_char(const char buf)
{
	while((USART4->ISR & (0X1<<7)) != (0X1<<7));
	USART4->TDR = buf;	
	while((USART4->ISR & (0X1<<6)) != (0X1<<6));
}
char* get_string()
{
	static char str[32];
	for(int i=0;i<sizeof(str)-2;i++)
	{
		str[i] = get_char();
		put_char(str[i]);
		if(str[i] == '\r')
		{
			put_char('\n');
			str[i+1] = '\n';
			str[i+2] = '\0';
			break;
		}
	}
	return str;
}
char get_char()
{
	while((USART4->ISR & (0X1<<5)) != (0X1<<5));
	return (char)USART4->RDR;
}

1.输入a输出b