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问 我正在用mega16操纵DS18B20，但是现在用ICCAVR怎么也写不出可以正常工作的程序。不知哪位大侠有这方面的经验啊？ 答 1: 这是某位网友的作品（可能就是在21ic下载的，我借助它编写了PPC8260上面读DS2520的程序，不敢掠美，特希望作者现一下身）

#include "io2313.h"
#include "macros.h"

#define BOOL  unsigned char
#define TRUE  1
#define FALSE 0

#define SET_BIT(x, y)   (x|=(1<<y))
#define CLR_BIT(x, y)   (x&=~(1<<y))
#define GET_BIT(x, y)   ((x&(1<<y))>>y)

#define PULLING_LOW()   SET_BIT(DDRD, 0)  
#define PULLING_UP()    CLR_BIT(DDRD, 0)  
#define READ_DQ()       GET_BIT(PIND, 0)

#define SKIP_ROM        0xCC
#define READ_RAM        0xBE
#define CONVERT_T       0x44

void ShortDelay(unsigned char tt)
{
    asm("_L2: subi R16,1");            // 1t
    asm(" nop")                        // 1t
    asm(" brne _L2");                  // 2t/1t
    asm(" nop");                       // 1t
    asm(" ret");                       // 4t
}

unsigned char W1_Reset()
{
    unsigned char c;
    PULLING_LOW();
    ShortDelay(198);                   // 500us
    ShortDelay(198);
    ShortDelay(198);
    ShortDelay(198);
    ShortDelay(198);
    PULLING_UP();
    ShortDelay(148);                   // 75us
    c = READ_DQ();
    if (c == 0x01)
    {
        return FALSE;
    }
    ShortDelay(198);                   // 300us
    ShortDelay(198);
    ShortDelay(198);
    c = READ_DQ();
    if (c == 0x00)
    {
        return FALSE;
    }
    return TRUE;
}

unsigned char W1_BitIO(unsigned char b)
{
    if (b)
    {
        PULLING_LOW();
        ShortDelay(2);                 //2us
        PULLING_UP();
        ShortDelay(18);                //10us
        b = READ_DQ();
        ShortDelay(118);               //60us
    }
    else
    {
        PULLING_LOW();
        ShortDelay(2);                 //2us
        PULLING_LOW();
        ShortDelay(18);                //10us
        b = READ_DQ();
        ShortDelay(118);               //60us
        PULLING_UP();
    }
    return b;
}

unsigned char W1_SendByte(unsigned char c)
{
    unsigned char i = 8;
    do
    {
        c = c>>1|(W1_BitIO(c&1)?0x80:0);
    } while(--i);
    return c;
}

unsigned char W1_ReadByte()
{
    return W1_SendByte(0xFF);
}

unsigned char W1_Command(unsigned c)
{
    if (W1_Reset())
    {
        W1_SendByte(SKIP_ROM);
        W1_SendByte(c);
        return 1;
    }
    else
    {
        return 0;
    }
}

int ReadTemperature()
{
     union
    {
        unsigned char c[2];
        int i;
    } temp;
    
    if (W1_Command(READ_RAM))
    {
        temp.c[0] = W1_ReadByte();
        temp.c[1] = W1_ReadByte();
        if (W1_Command(CONVERT_T))
        {
            ;   
        }
        else
        {
            return -1000;
        }
        return (int)(temp.i*5/4+1)/2;
    }
    else
    {
        return -1000;
    }
}
答 2: 谢谢hudaidai了，也感谢原作者。谢谢两位了，我来用用看吧！ 答 3: thank very much 答 4: 有本介绍icc的书上有现成的原程序 答 5: 我的网上有