main.c

44b0/linux环境基本实验源码,包括helloworld,线程,串口,AD,DA,CAN总线,LED,电机,GPS,GPRS,键盘驱动等

/************************************************\
*	by threewater<[e-mail]>	*
*		2003.12.18			*
*						*
\***********************************************/

#include <stdio.h>
#include <fcntl.h>
#include <string.h>
//#include <sys/types.h>
//#include <sys/ipc.h>
#include <sys/ioctl.h>
#include "hardware.h"
#include "exio.h"
#include "s3c44b0-spi.h"

#define MAX504_CS			0x2		//EXIO1
#define MAX504_CLR			0x1		//EXIO0

#define SIOLSB				0x40
#define MAX504_CLEAR()			do{CLREXIOBIT(MAX504_CLR);	Delay(1); SETEXIOBIT(MAX504_CLR);}while(0)

#define Max504_FULL			4.096f

#define SPI_DEV		"/dev/spi/0"
static int spi_fd = -1;

void Delay(int t)
{
	int i;
	for(;t>0;t--)
		for(i=0;i<400;i++);
}


void Max504_SetDA(int value)
{
	value<<=2;
	MAX504_CLEAR();
	Delay(1);
	
	ioctl(spi_fd, SPI_IOCTRL_WFORMAX504, value);
}

int main(int argc, char **argv)
{
	float v;
	int value;

	if(argc!=2){
		printf("Error parameter\n");
		return 1;
	}
	sscanf(argv[1], "%f",&v);	
	if(v<0 || v>Max504_FULL){
		printf("DA out must between: 0 to %f\n", Max504_FULL);
		return 1;
	}
	
	init_exio();
	if((spi_fd=open(SPI_DEV, O_NONBLOCK))<0){
		printf("Error opening %s spi device\n", SPI_DEV);
		return 1;
	}
	
	value=(int)((v*1024.0f)/Max504_FULL);
	Max504_SetDA(value);
	
	close(spi_fd);                                                         
	printf("Current Voltage is %f V\n", v);
	return 0;
}