#include    "uart4.h"

void uart4_init()
{
        //使能GPIO
        RCC->MP_AHB4ENSETR  |=(0x1<<1);
        RCC->MP_AHB4ENSETR  |=(0x1<<6);
        //使能UART4
        RCC->MP_APB1ENSETR |=(0x1<<16) ;

        //GPIO  MODER设置  复用模式设置
        GPIOB->MODER    |=(0x2<<4);
        GPIOG->MODER    |=(0x2<<22);
        
        GPIOB->AFRH     |=(0x8<<8);
        GPIOG->AFRH     |=(0x6<<12);

        //UART设置
        //UE
        USART4->CR1      &=(~(0x1));
        //8位数据位
        USART4->CR1     &=(~(0x1<<12));
        USART4->CR1     &=(~(0x1<<28));
        //采样设置
        USART4->CR1     &=(~(0x1<<15));
        //校验位设置
        USART4->CR1     &=(~(0x3<<10));

        //数据发送      接收    使能uart4
        USART4->CR1     |=(0x1<<3);
        USART4->CR1     |=(0x1<<2);
        USART4->CR1     |=(0x1<<0);

        //停止位        时钟不分蘋
        USART4->CR2     &=(~(0x3<<12));
        USART4->PRESC   &=(~(0xF));

        //波特率设置
        USART4->BRR     =0x22B;

}


//消息接收
char msr_recv()
{
        char a;
        while(!(USART4->ISR &(0x1<<5)));
        a=USART4->RDR;
        return  a;
}

void putchar(char a)
{
   
    while(!(USART4->ISR&(0x1<<7)));
   USART4->TDR=a;
    while(!(USART4->ISR&(0x1<<6)));
}