1-wire1.c

本文介绍了一种电子密码锁的ds2401的实现源码和文档。该电子密码锁采用1一wire总线芯片.

/*
By George Elefteriadis.24/8/[e-mail]

This program reads the code of all 1-wire devices.The microcontroller is an AT90S2313.
Connect a resistor between PD2 and 5V an connect the ibutton in PD2 and ground.The program
is tested in MCU00100 board and uses the Uart to display the code and PORTB to display the
CRC as it calculated by the routine of crc.In case of wrong reading the transaction goes from
the beginning and theres no chance of displaying a wrong byte.*/

#include<stdio.h>
#include<90s2313.h>
#include<delay.h>
#include<mem.h> 
char table[]="0123456789ABCDEF";
char code[8];

//send read rom-0x33 on 1-wire 
void command(unsigned char read)
{ 
int j;
unsigned char i;
for (j=0;j<=7;j++){
i=read&1;
if (i==1){
PORTD.2=0;
delay_us(9);
PORTD.2=1;
delay_us(90);
}
else{
PORTD.2=0;
delay_us(90);
PORTD.2=1;
delay_us(9);
}
read=read>>1;
}
}
//end of read rom command 

//store the ascii characters in sram location 0xa0-0xaf
void sram(unsigned char store)
{
unsigned char l,q,i,z,index;
index=peekb(0x61);
l=store;
q=l&0x0f;
i=l&0xf0;
i=i>>4;
i=i+0x80;
z=peekb(i);
pokeb(index,z);
q=q+0x80;
z=peekb(q);
index++;
pokeb(index,z);
index++;
pokeb(0x61,index);
}
//end of store

//read the 8 bytes of code
unsigned char read(void)
{
int j,f;
unsigned char byte;
byte=0x00;
for(f=0;f<=7;f++){
for (j=0;j<=7;j++){
PORTD.2=0;
delay_us(6);
PORTD.2=1;
delay_us(13);
if (PIND.2==1)
{
byte=byte>>1;
byte=byte|0x80;
}
else {
byte=byte>>1;
}
delay_us(765);
}
code[f]=byte;
}
return byte;
}
//end of read function

//the cyclic redundancy check
void crc(unsigned char byte)
{
unsigned char crc,bit0,cbit,r;
int i;
crc=peekb(0x60);
for(i=0;i<=7;i++)
{
cbit=crc&0x01;
bit0=byte&0x01;
crc=crc>>1;
r=cbit^bit0;
if(r==1)
{
crc=crc^0x8c;
}
byte=byte>>1;
}
pokeb(0x60,crc);
} 
//end of crc
      
main()
{
unsigned char testcrc,q,i; 
int m;
UBRR=25;
UCR=0x18; 
DDRD=0xff;
PORTD=0xff;
DDRB=0xff;
PORTB=0xff;

start: 
pokeb(0x60,0x00);
pokeb(0x61,0xa0);
reset_pulse:    
PORTD.2=0;//cbi portd,2
delay_us(500);
PORTD.2=1;//sbi portd,2
delay_us(45);
if (PIND.2==1){
goto reset_pulse;
}
while (PIND.2==0){
}
delay_us(220);

command(0x33);
read();

for(m=0;m<=7;m++)
{
sram(code[m]);
}

for(m=0;m<=6;m++){
crc(code[m]);
}
testcrc=peekb(0x60); 
pokeb(0xb0,0x0d);
if(testcrc==code[7]){
if(code[7]!=0){
PORTB=testcrc;
for(q=0xa0;q<=0xb1;q++){
i=peekb(q);
putchar(i);
delay_ms(250); 
}
}
}
goto start;
}

/*for (q=0x60;q<=0x67;q++)
pokeb(q,read());

for (q=0x60;q<=0x67;q++){
byte0=peekb(q);
byte0=0xff-byte0;*/