ARM day6

 uart4.h:

#ifndef __UART_H__
#define __UART_H__

#include  "stm32mp1xx_gpio.h"

 #include  "stm32mp1xx_rcc.h"

 #include "stm32mp1xx_uart.h"

void uart4_init();
void putchar(char a);
char getchar();
#define RCCT (*(unsigned int *)0X50000A28)
#define GPIOE_MODER (*(unsigned int *)0X50006000)
#define GPIOF_MODER (*(unsigned int *)0X50007000)
#define GPIOE_OTYPER (*(unsigned int *)0X50006004)
#define GPIOE_OSPEEDR (*(unsigned int *)0X50006008)
#define GPIOE_OPUPDR (*(unsigned int *)0X5000600C)
#define GPIOE_ODR (*(unsigned int *)0X50006014)
#define GPIOF_OTYPER (*(unsigned int *)0X50007004)
#define GPIOF_OSPEEDR (*(unsigned int *)0X50007008)
#define GPIOF_OPUPDR (*(unsigned int *)0X5000700C)
#define GPIOF_ODR (*(unsigned int *)0X50007014)
void all_led_init();
void LED1_ON();
void LED2_ON();
void LED3_ON();
void LED1_OFF();
void LED2_OFF();
void LED3_OFF();

#endif 

uart4.c:

 #include "uart4.h"

void uart4_init()
{
//使能GPIOB GPIOG UART4外设时钟
    RCC->MP_AHB4ENSETR |= (0x1<<1);//GPIOB
    RCC->MP_AHB4ENSETR |= (0x1<<6);//GPIOG
    RCC->MP_APB1ENSETR |= (0X1<<16);//UART4
    //设置PB2和PG11管脚复用
    //PB2
    GPIOB->MODER &= (~(0x3<<4));
    GPIOB->MODER |=(0x2<<4); 
    GPIOB->AFRL &= (~(0XF<<8));
    GPIOB->AFRL |= (0x8<<8);
    //PG11
    GPIOG->MODER &= (~(0x3<<22));
    GPIOG->MODER |=(0x2<<22); 
    GPIOG->AFRH &= (~(0XF<<12));
    GPIOG->AFRH |= (0x6<<12);
    //设置串口不使能 UE=0
    USART4->CR1 &= (~(0X1));
    //设置8位数据位
    USART4->CR1 &= (~(0x1<<12));
    USART4->CR1 &= (~(0x1<<28));
    //设置没有奇偶校验位
    USART4->CR1 &= (~(0x1<<10));
    //设置1位停止位
    USART4->CR2 &= (~(0x3<<12));
    //设置16倍过采样
    USART4->CR1 &= (~(0x1<<15));
    //设置时钟不分频
    USART4->PRESC &= (~(0xF));
    //设置波特率为115200
    USART4->BRR=0X22B;
    //使能发送器
    USART4->CR1 |= (0x1<<3);
    //使能接收器
     USART4->CR1 |= (0x1<<2);
    //使能uart4
     USART4->CR1 |= (0x1<<0);
}

//发送一个字符
void putchar(char a)
{
    //先判断发送数据寄存器是否为空
     //不为空阻塞等待
    while(!(USART4->ISR&(0x1<<7)));
    //为空向发送数据寄存器写入a的数据
   USART4->TDR=a;//写入数据
    //写入完成需要判断发送是否完成，不完成阻塞等待，完成了则函数结束
    while(!(USART4->ISR&(0x1<<6)));
}

//接收一个字符
char getchar()
{
    char a;
    //先判断接收数据寄存器中有没有准备好的数据
    //如果数据没有准备好则阻塞等待
    while(!(USART4->ISR&(0x1<<5)));
    //如果数据准备好了则读取
    a=USART4->RDR;
    //读取完毕将读取到的数据返回
    return a;
}
void all_led_init()//led灯的初始化
{
    //GPIOE/GPIOF时钟使能
   RCCT  |= (0x3<<4);
    //PE10设置为输出
    GPIOE_MODER &= (~(0X3<<20));
    GPIOE_MODER |= (0X1<<20);
    //PF10设置为输出
    GPIOF_MODER &= (~(0X3<<20));
    GPIOF_MODER |= (0X1<<20);
    //PE8设置为输出
    GPIOE_MODER &= (~(0X3<<16));
    GPIOE_MODER |= (0X1<<16);
    //PE10设置为推挽输出
    GPIOE_OTYPER &= (~(0X1<<10));
    //PF10设置为推挽输出
    GPIOF_OTYPER &= (~(0X1<<10));
    //PE8设置为推挽输出
    GPIOE_OTYPER &= (~(0X1<<8));
    //PE10设置为低速输出
    GPIOE_OSPEEDR &= (~(0X3<<20));
    //PF10设置为低速输出
    GPIOF_OSPEEDR &= (~(0X3<<20));
    //PE8设置为低速输出
   GPIOE_OSPEEDR &= (~(0X3<<16));
    //PE10无上拉下拉电阻
    GPIOE_OPUPDR &= (~(0X3<<20));
    //PF10无上拉下拉电阻
    GPIOF_OPUPDR &= (~(0X3<<20));
    //PE8无上拉下拉电阻
    GPIOE_OPUPDR &= (~(0X3<<16));

    //三盏灯默认输出低电平
    GPIOE_ODR &= (~(0X1<<10));
   GPIOF_ODR &= (~(0X1<<10));
    GPIOE_ODR &= (~(0X1<<8));
}

//led1亮
void LED1_ON()
{
    GPIOE_ODR |= (0X1<<10);
}
//led2亮
void LED2_ON()
{
   GPIOF_ODR |= (0X1<<10);
}
//led3亮
void LED3_ON()
{
    GPIOE_ODR |= (0X1<<8);
}

//LED1灭
void LED1_OFF()
{
     GPIOE_ODR &= (~(0X1<<10));
}
//LED2灭
void LED2_OFF()
{
     GPIOF_ODR &= (~(0X1<<10));
}
//LED3灭
void LED3_OFF()
{
     GPIOE_ODR &= (~(0X1<<8));
}    

main.c：

#include "uart4.h"
void delay(int ms)
{
    int i,j;
    for(i=0;i<ms;i++)
    {
        for(j=0;j<2000;j++)
        {}

    }
}

int main()
{
        //串口初始化
    uart4_init();
    //led灯的初始化
   all_led_init();
    char i;
    while(1)
    {
         i=getchar();
        putchar(i);
        switch (i)
        {
        case 'a':
         LED1_ON();
        LED2_OFF();
        LED3_OFF();
            break;
        case 'b':
        LED1_ON();
        LED2_OFF();
        LED3_OFF();
            break;
        case 'c':
        LED1_ON();
        LED2_OFF();
        LED3_OFF();
            break;
       
        default:
        LED1_ON();
        LED2_ON();
        LED3_ON();
            break;
        }
     
    }
 
    return 0;
}