mcp41010.c.130220145238

ATmega16-ad1602

#include<iom16v.h>

#define r_full		9340

#define cs_ddr		DDRA
#define cs_port		PORTA
#define sck_ddr		DDRA
#define sck_port	PORTA
#define si_ddr		DDRA
#define si_port		PORTA
#define cs			0x01
#define sck			0x02
#define si			0x04

void r_io_init(void)
{
	cs_ddr|=cs;
	sck_ddr|=sck;
	si_ddr|=si;
	cs_port|=cs;
	sck_port&=~sck;
	si_port&=~si;
}

void write_r(unsigned char cmd,unsigned char dat)			//cmd=0x11:write data;	cmd=0x31:cut off
{
	unsigned char count=0;
	sck_port&=~sck;//sck=0
	si_port&=~si;//si=0
	cs_port&=~cs;//cs=0
	sck_port|=sck;				//0
	sck_port&=~sck;
	sck_port|=sck;				//1
	sck_port&=~sck;
	if(cmd&0x20)
		si_port|=si;
	else
		si_port&=~si;
	sck_port|=sck;				//2
	sck_port&=~sck;
	if(cmd&0x10)
		si_port|=si;
	else
		si_port&=~si;
	sck_port|=sck;				//3
	sck_port&=~sck;
	si_port&=~si;
	sck_port|=sck;				//4
	sck_port&=~sck;
	sck_port|=sck;				//5
	sck_port&=~sck;
	if(cmd&0x02)
		si_port|=si;
	else
		si_port&=~si;
	sck_port|=sck;				//6
	sck_port&=~sck;
	if(cmd&0x01)
		si_port|=si;
	else
		si_port&=~si;
	sck_port|=sck;				//7
	sck_port&=~sck;
	for(count=0;count<8;count++)
	{
		if(dat&0x80)
			si_port|=si;
		else
			si_port&=~si;
		sck_port|=sck;
		sck_port&=~sck;
		dat=dat<<1;
	}
	cs_port|=cs;
}

void r_init(void)
{
	r_io_init();
	write_r(0x11,0x7f);
}

void set_r(unsigned int r)
{	
	float buf0=0;
	unsigned char buf1=0;
	buf0=r_full/255;
	buf0=r/buf0;
	buf1=(unsigned char)buf0;
	write_r(0x11,buf1);
}











//main.c


void main(void)
{
	r_init();
	while(1)
	{
		set_r(4900);
	}
}