1wire.c

通过车载终端采集GPS数据

#include "w77e532.h"
#include "1wire.h"
#include <intrins.h>
/************************************************************
*Function:延时处理
*parameter:
*Return:
*Modify:
*************************************************************/
void TempDelay (unsigned char us)
{
    while(us--);
}


/****************************************
*1-wire reset function
*call this function before rom command and function command
*return value:1 :have 1-wire device;0: no 1-wire device
******************************************/
unsigned char wire1_reset()
{
    bit presence;
    WIRE1_DQ = 1;
    _nop_();
    WIRE1_DQ = 0;
    TempDelay(86);   //delay 530 uS//80
    _nop_();    
    WIRE1_DQ = 1;
    TempDelay(14);   //delay 100 uS//14
    _nop_();
    _nop_();
    _nop_();

    presence = WIRE1_DQ;
    TempDelay(40);       //20//mod to 40//09-19
    _nop_();
    _nop_();
    WIRE1_DQ = 1;
    if (0 == presence)
        return 1;
    else
        return 0;
}


/******************************************
*read a bit
*return value: the bit readed
*******************************************/
unsigned char wire1_readbit()
{
    unsigned char retVal, i;
    WIRE1_DQ = 0;
    i++;
    WIRE1_DQ = 1;
    i++;
    i++;
    i++;
    retVal = WIRE1_DQ;
    for(i=0; i<19; i++);
    return retVal;
}

/*******************************************
*write a bit
*bitval:write value
*******************************************/
void wire1_writebit(unsigned char bitval)
{
    unsigned char i;
    WIRE1_DQ = 0;
    i++;
    if (bitval == 1)
        WIRE1_DQ = 1;
    for(i=0; i<18; i++);
    WIRE1_DQ = 1;
}

/********************************************
*
*********************************************/
unsigned char wire1_readbyte()
{
    unsigned char i,u=0;
    unsigned char temp;
    for(i=0;i<8;i++)
    {
        WIRE1_DQ = 0;
        u >>= 1;
        WIRE1_DQ = 1;
        temp = WIRE1_DQ;
        if(temp==1)
            u |= 0x80;
        TempDelay(12);//25);//4);//mod to 12 09-19
    /**add09-19**/
        WIRE1_DQ = 1;
        TempDelay(1);
    /*end of add*/
        _nop_();
    }
    return(u);
}

/*******************************************
*
*******************************************/
void wire1_writebyte(unsigned char value)
{
    unsigned char i;
    for (i=0;i<8;i++)
    {
        WIRE1_DQ = 0;
        _nop_();
        WIRE1_DQ = value & 0x01;
        TempDelay(13);//25);//5);   //delay 45 uS //5//mod to 13 09-19
        _nop_();
        _nop_();
        WIRE1_DQ=1;
        value >>= 1;
        //add 
        TempDelay(1);
    }
}