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C语言 cortex-A7核UART总线实验

news 2025/7/6 20:05:05

一、C

1）uart4.h

#ifndef __UART4_H__                       
#define __UART4_H__                       #include "stm32mp1xx_rcc.h"               
#include "stm32mp1xx_gpio.h"              
#include "stm32mp1xx_uart.h"              //PB2 ---> UART4_RX                       
//PG11 ---> UART4_TX                      //RCC/GPIO/UART4章节初始化                
void hal_uart4_init();                    
//发送一个字符                            
void hal_put_char(const char ch);         
//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();                   #endif

2）uart.c

#include "uart4.h"//RCC/GPIO/UART4章节初始化
void hal_uart4_init()
{//RCC章节初始化//1.使能GPIOB组控制器  MP_AHB4ENSETR[1] = 1  0x50000A28[1]RCC->MP_AHB4ENSETR |= (0X1 << 1);//2.使能GPIOG组控制器  MP_AHB4ENSETR[6] = 1  0x50000a28[6]RCC->MP_AHB4ENSETR |= (0X1 << 6);//3.使能UART4组控制器  MP_AHB4ENSETR[11] = 1 PB2 PG11---> 0x500000A00[16] RCC->MP_APB1ENSETR |= (0X1 << 16);//GPIO章节初始化//1.设置PB2引脚为复用功能模式 MODER[5:4] = 10GPIOB->MODER &= (~(0x1 << 4));GPIOB->MODER |= (0x1 << 5);//2.设置PB2引脚复用功能为UART4_RX功能 AFRL[11:8] = 1000GPIOB->AFRL &= (~(0xf << 8));GPIOB->AFRL |= (0x1 << 11);//设置PG11引脚为复用功能模式 MODER[23:22] = 10GPIOG->MODER &= (~(0x1 << 22));GPIOG->MODER |= (0x1 << 23);//设置PG11引脚复用功能为UART4_TX功能 AFRH[15:12] = 0110GPIOG->AFRH &= (~(0xf << 12));GPIOG->AFRH |= (0x6 << 12);//UART4章节初始化//8N1 115200 使能位 代码编写逻辑//0.设置串口UE=0 CR1[0] = 0USART4->CR1 &= (~(0x1 << 0));//1.设置1位起始位，8位数据位 CR1[28][12] = 00USART4->CR1 &= (~(0x1 << 12));USART4->CR1 &= (~(0x1 << 28));//2.设置串口1位停止位 CR2[13:12] = 00USART4->CR2 &= (~(0x3 << 12))	;//3.设置串口无校验位 CR1[10] = 0USART4->CR1 &= (~(0x1 << 10));//4.设置串口16倍采样率 CR1[15] = 0USART4->CR1 &= (~(0x1 << 15));//5.设置串口不分频 PRESC[3:0] = 0000USART4->PRESC &= (~(0xf << 0));//6.设置串口波特率为115200 BRR = 0X22bUSART4->BRR &= (~(0xffff));USART4->BRR |= (0x22b);//7.设置串口发送位使能 CR1[3] = 1USART4->CR1 |= (0x1 << 3);//8.设置串口接受位使能 CR1[2] = 1USART4->CR1 |= (0x1 << 2);//9.设置串口使能 CR1[0] = 1USART4->CR1 |= (0x1 << 0);
}
//发送一个字符
void hal_put_char(const char ch)
{//1.判断发送数据寄存器是否为空 ISR[7]//读0：发送数据寄存器满，需要等待 for while//读1：发送数据寄存器空，可以发送数据while(!(USART4->ISR & (0X1 << 7)));//2.将参数ch传递过来的内容，赋值给TDR寄存器USART4->TDR = (volatile unsigned int)ch;	//3.判断一帧数据是否发送完成 ISR[6]while(!(USART4->ISR & (0x1 << 6)));
}//发送一个字符串
void hal_put_string(const char* string)
{//判断字符串是否为'\0'int i=0;while(string[i] != '\0'){//一个字符一个字符进行发送hal_put_char(string[i]);i++;}
}//接收一个字符
char hal_get_char()
{char ch;//1.判断接收数据寄存器是否不为空 ISR[5]//读0：没有接收到数据，需要等待 for while//读1：接收到数据，可以将数据读出while(!(USART4->ISR & (0x1 << 5)));//2.将接收数据寄存器中RDR，读出来ch = (char)USART4->RDR;return ch;
}char buffer[50] = {0};
//接收一个字符串
char* hal_get_string()
{for(int i=0;buffer[i]!='\0'; i++){buffer[i]='\0';}//判断键盘enter是否按下'\r'int i = 0;char ch;while(1){ch = hal_get_char();hal_put_char(ch);buffer[i] = ch;i++;if(ch == '\r'){hal_put_char('\n');	break;			}}buffer[i] = '\n';return buffer;
}

3）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()                                                            
{                                                                     hal_uart4_init();                                                 while(1)                                                          {                                                                 //单个字符                                                    //hal_put_char(hal_get_char() + 1);                           //字符串                                                      hal_put_string(hal_get_string());                             }                                                                 return 0;                                                         
}