uart_driver.c

ARM9系列,s3c2410实验代码

/*
 *	uart_driver.c - uart driver ( low-level )
 *	
 *	Author: 	li ming <[e-mail]>
 *	Date:		2005-6-11
 *	Copyleft:	http://www.lumit.org
 */

#include "uart_driver.h"

int UART_BASE;
int UART_BAUD;

/* set uart related gpio */
int uart_open( int uart_base )
{	
	UART_BASE = uart_base;
	
	/* Disable interrupts  */
	*(volatile unsigned *) (UART_BASE + UCON) = 0;
	
	/* Set port for 8 bit, one stop, no parity  */
	*(volatile unsigned *) (UART_BASE + ULCON) = (ULCR8bits);
	
	/* Enable interrupt operation on UART */
	*(volatile unsigned *) (UART_BASE + UCON) = UCRRxM | UCRTxM;
   
	return 0;
}

int uart_read( unsigned char * buf, int count )
{	
	int i;
	unsigned char ch;
	
	for( i = 0; i < count; i++ )
	{
		/* read rx ready flag, when =1 break */
		while ( (RX_DATA(GET_STATUS(UART_BASE)))==0 ) 
			;		
	
		ch = GET_CHAR(UART_BASE);
		
		*(buf+i) = ch;
	}
	
	return count;
}

int uart_write( unsigned char * buf, int count )
{	
	int i;
	unsigned char ch;
	
	for( i = 0; i < count; i++ )
	{
		ch = *(buf+i);
		
		/* read tx ready flag, when =1 break */
		while ( TX_READY(GET_STATUS(UART_BASE))==0)
			;
		
		PUT_CHAR(UART_BASE, ch);
	}
	
	return count;
}

int uart_ioctl( unsigned int cmd, unsigned long arg )
{	
	
	switch( cmd )
	{
		case	UART_SELECT_CHANNEL:			
			UART_BASE = arg;
			break;	
		case	UART_SET_BAUDRATE:			
			UART_BAUD = arg;
			*(volatile unsigned *) (UART_BASE + UBRDIV) = UART_BAUD;
			break;
		default:
			break;
	}
	

	return 0;
}

int uart_release( void )
{
	// do nothing 
	return 0;	
}