uart.c

arm开发很好的例程

#include <stdarg.h>
#include <stdio.h>
#include "bios.h"
#include "uart.h"

void uart_init(void)
{	
//	*pDMA7_PERIPHERAL_MAP=0x7000;   //setting up the UART TX DMA regsiter
	*pUART_GCTL=0x1;                //enabling the UART Clocks
	*pUART_LCR=0x0000;              //Reset LCR regsiter
	*pUART_IER=0x0000;              //enabling the receive and transmit buffer full interrupt
	//*pDMA7_CONFIG=0x0000;           //enabling autobuffer mode
	//*pDMA7_START_ADDR=buffer;      //setting the pointer to the file as the starting address of the DMA
	//
	////there are 24 characters in the buffer[] as defined above
	//*pDMA7_X_COUNT=sizeof(buffer);               //setting the count
	//
	//*pDMA7_X_MODIFY=0x1;            //modifying register
	*pUART_LCR=0x0083;              //enabling 8 bits,1stop bit,no parity
	
	//see note at top for different baud rate settings
	*pUART_DLL=0x48;                //setting the baud rate
	
	*pUART_LCR=0x0003;              //enabling 8 bits,1stop bit,no parity
	//*pDMA7_CONFIG=0x0001;           //starting the DMA transfer
}



UNS8 get_char(void)
{
	while( (*pUART_LSR&0x0001) == 0 ){}
	
	return *pUART_RBR;
}

UNS8 get_char_no(void)
{
	return *pUART_RBR;
}



void put_char(UNS8 ch)
{
	
	while( (*pUART_LSR&0x0020) == 0 ){}
	*pUART_THR = ch;
	
}



UNS8 get_ch(void)
{
	UNS8 temp;
	
	temp = get_char();
	put_char(temp);
	return temp;
}

void put_str(UNS8 *pStr,UNS8 size)
{
    if( size != 0 )
    {	
		for( ;size >0;size --)
		{
			put_char(*pStr);
			pStr++;
		}
	}
	else
	{
		while(*pStr)
		{
			put_char(*pStr);
			pStr++;
		}	
	}
}

UNS16 get_str(S8 *buf,UNS16 size)
{
	S8 temp;
	UNS16 i;
	for(i=0;;i++)
	{
		temp = get_ch();	
		if((temp == '\r' )||(i >= size))
			break;
		*buf = temp;
		buf++;
	}
	*buf='\r';
	buf++;
	*buf ='\0'; 
	return i;
}


void my_printf(char *fmt, ...)
{
	va_list ap;
    char string[256];    

    va_start(ap, fmt);
    vsprintf(string, fmt, ap);
    put_str((UNS8 *)string,0);
    va_end(ap);
}