ARMday06(串口)

代码：

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

void delay_ms(int ms)
{
    int i,j;
    for(i=0;i<ms;i++)
    {
      for(j=0;j<2000;j++);
    }
}
void init();
char getc();
void putc(char data);
void puts(char *data);
char *gets(void);
int main()
{
	init();//初始化
	puts("jntm test");
	while(1){
		puts(gets());
	}
	return 0;
}
void init(){
	/*RCC章节*/
	//设置UART4的RCc时钟使能
    //RCC_MP_APB1ENSETR[16]->1
    RCC->MP_APB1ENSETR |= (0x1<<16);
    //设置GPIOB和GPIOG的时钟使能
    //RCC_MP_AHB4ENSETR[6]->1
    //RCC_MP_AHB4ENSETR[1]->1
    RCC->MP_AHB4ENSETR |= (0x1<<1);
    RCC->MP_AHB4ENSETR |= (0X1<<6);

	/*-- GPIO章节--*/
    //设置PG11和PB2功能复用为UART4功能
    //PG11
    //GPIOG_MODER[23:22]->10
    GPIOG->MODER &= (~(0X3<<22));
    GPIOG->MODER |= (0X2<<22);
    //GPIOG_AFRH[15:12]->0110    
    GPIOG->AFRH &= (~(0xf<<12));
    GPIOG->AFRH |= (0x6<<12);
    //PB2
    //GPIOB_MODER[5:4]->10
    //GPIOB_AFRL[11:8]->1000
    GPIOB->MODER &= (~(0x3<<4));
    GPIOB->MODER |= (0X2<<4);
    GPIOB->AFRL &= (~(0xF<<8));
    GPIOB->AFRL |= (0x8<<8);

	/*--UART4章节--*/
	
    //禁用串口
	if(USART4->CR1 & 0X1){
		delay_ms(500);
	    USART4->CR1 &=(~(0x1 << 0));
	}
    //设置数据8个数据位 CR1[28]->0  CR1[12]-》0
    USART4->CR1 &= (~(0X1<<28));
    USART4->CR1 &= (~(0X1<<12));
    //设置没有校验位CR1[10]->0
    USART4->CR1 &= (~(0X1<<10));
    //设置1个停止位CR2[13:12]->00
    USART4->CR2 &= (~(0x3<<12));
    //设置16倍采样 CR1[15]->0
    USART4->CR1 &= (~(0X1<<15));
    //设置波特率为115200 BRR=0X22B
    USART4->BRR |= 0X22B;
    //设置1分频 PRESC[3:0]->0000
    USART4->PRESC &= (~(0XF << 0));
    //使能发送器 CR1[3]->1
    USART4->CR1 |= (0X1<<3);
    //使能接收器 CR1[2]->1
    USART4->CR1 |= (0X1<<2);
    //使能串口 CR1[0]->1
    USART4->CR1 |= (0X1); 
}
void putc(char data)
{
//判断发送数据寄存器有没有数据，没有数据时可以发送
    while(!(USART4->ISR&(0X1<<7)));
    USART4->TDR=data;//将要发送的数据保存在发送寄存器中
    while(!(USART4->ISR&(0X1<<6)));//数据传输完成，函数结束
}
char getc(void)
{
	char ch;
	while(!(USART4->ISR & (0x1 << 5)));
	ch = USART4->RDR;
	return ch;
}
void puts(char *data){
	char *c=data;
	for(;*c!='\0';c++){
		putc(*c);
	}
	putc(*c);
	putc('\n');
	putc('\r');
}
char data[50]="";
char *gets(void){
	int i;
	for(i=0;i<49;i++){
	
		data[i]=getc();
		putc(data[i]);
		if(data[i]=='\r')
			break;
	}
	data[i]='\0';
	putc('\n');
	return data;
	
}

what a pity,can't run

now，it can run