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2012-07-31 17:58:17

/************************************************

DS18B20的驱动,在TX2440A开发板上做测试

维护记录:  2009-10-30  V1.0  

linux内核:2.6.31

硬件接法:

        DQ --> GPB5

驱动用法:

        设备名称:TX2440-ds18b20

*************************************************/

#include

#include

#include

#include

#include

#include

#include

//#include

#include

//#include

#include

#include

#include

 

#define DQ_PIN       S3C2410_GPB(5)

#define DQ_PIN_OUTP  S3C2410_GPIO_OUTPUT

#define DQ_PIN_INP   S3C2410_GPIO_INPUT

#define HIGH 1

#define LOW 0

 

//定义DS18B20ROM指令

#define    DS18B20_ReadROM        0x33    //ROM

#define    DS18B20_MatchROM       0x55    //匹配ROM

#define    DS18B20_SkipROM        0xCC    //跳过ROM

#define    DS18B20_SearchROM      0xF0    //搜索ROM

#define    DS18B20_AlarmROM       0xEC    //报警搜索

 

//定义DS18B20存储器操作命令

#define    DS18B20_WriteSCR       0x4E    //写暂存存储器

#define    DS18B20_ReadSCR        0xBE    //读暂存存储器

#define    DS18B20_CopySCR        0x48    //复制暂存存储器

#define    DS18B20_ConvertTemp    0x44    //温度变换

#define    DS18B20_RecallEP       0xB8    //重新调出

#define    DS18B20_ReadPower      0xB4    //读电源

 

typedef unsigned char U8;

typedef unsigned short U16;

 

#define DEVICE_NAME  "TX2440-ds18b20"    /* 设备名称 */     

static int DS18B20_Major = 0;           /* 主设备号 */

 

U16 temp;

U8 DS18B20_ID[8] = {0};

 

U8 DS18B20_Init(void)

{  

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_OUTP);

    s3c2410_gpio_setpin(DQ_PIN, LOW);

    udelay(700);

    s3c2410_gpio_setpin(DQ_PIN, HIGH);

    udelay(4);

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_INP);

    udelay(100);

   

/*  if(s3c2410_gpio_getpin(DQ_PIN)!=0) //测试复位是否成功

    {

        printk("There are no 18B20 at GPB5! 0x%x\n");

        return 1;

    }

    else

        printk("Init 18B20 succeed!\n");

*/

    return 0;

}

 

U8 DS18B20_ReadBit(void)   

{

    U8 dat;

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_OUTP);

    s3c2410_gpio_setpin(DQ_PIN, LOW);

    udelay(2);

    s3c2410_gpio_setpin(DQ_PIN, HIGH); //add

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_INP);

    udelay(10);

    if(s3c2410_gpio_getpin(DQ_PIN)!=0)

        dat=1;

    else

        dat=0;

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_OUTP);

    s3c2410_gpio_setpin(DQ_PIN, HIGH);//add

    udelay(50);

    return (dat);

}

 

U8 DS18B20_ReadByte(void)  

{

    U8 i,j,dat;

    dat=0;

    for(i=1;i<=8;i++)

    {

        j=DS18B20_ReadBit();

        dat=(j<<7)|(dat>>1);   //读出的数据最低位在最前面,这样刚好一个字节在DAT

    }

    return(dat);

}

 

void DS18B20_WriteByte(U8 dat)

{

    U8 j;

    U8 testb;

    s3c2410_gpio_cfgpin(DQ_PIN, DQ_PIN_OUTP);

    for(j=1;j<=8;j++)

    {

        testb=dat&0x01;

        dat=dat>>1;

        if(testb)    

        {

            s3c2410_gpio_setpin(DQ_PIN, LOW);

            udelay(8);

            s3c2410_gpio_setpin(DQ_PIN, HIGH);

            udelay(50);

        }

        else

        {

            s3c2410_gpio_setpin(DQ_PIN, LOW);

            udelay(90);

            s3c2410_gpio_setpin(DQ_PIN, HIGH);

            udelay(8);

 

        }

    }

}

 

void DS18B20_ReadID(void)

{

    udelay(1);

    DS18B20_Init();

    DS18B20_WriteByte(DS18B20_ReadROM);

    DS18B20_ID[0] = DS18B20_ReadByte();

    DS18B20_ID[1] = DS18B20_ReadByte();

    DS18B20_ID[2] = DS18B20_ReadByte();

    DS18B20_ID[3] = DS18B20_ReadByte();

    DS18B20_ID[4] = DS18B20_ReadByte();

    DS18B20_ID[5] = DS18B20_ReadByte();

    DS18B20_ID[6] = DS18B20_ReadByte();

    DS18B20_ID[7] = DS18B20_ReadByte();

}

 

void DS18B20_Match(void)

{

    DS18B20_WriteByte(DS18B20_MatchROM);

    DS18B20_WriteByte(DS18B20_ID[0]);

    DS18B20_WriteByte(DS18B20_ID[1]);

    DS18B20_WriteByte(DS18B20_ID[2]);

    DS18B20_WriteByte(DS18B20_ID[3]);

    DS18B20_WriteByte(DS18B20_ID[4]);

    DS18B20_WriteByte(DS18B20_ID[5]);

    DS18B20_WriteByte(DS18B20_ID[6]);

    DS18B20_WriteByte(DS18B20_ID[7]);

}

 

void DS18B20_TmpChange(void)

{

    while(DS18B20_Init());

    udelay(100);/*delay(1);*/

    DS18B20_WriteByte(DS18B20_SkipROM);  // address all drivers on bus

    DS18B20_WriteByte(DS18B20_ConvertTemp);  //  initiates a single temperature conversion

}

 

U16 DS18B20_Temperature(void)

{

    U8 a,b;

    while(DS18B20_Init());

    udelay(100);

    DS18B20_WriteByte(DS18B20_SkipROM);

    DS18B20_WriteByte(DS18B20_ReadSCR);

    udelay(4);

    a=DS18B20_ReadByte();

    b=DS18B20_ReadByte();

    temp=b;

    temp<<=8;             //two byte  compose a int variable

    temp=temp|a;

 

    return temp;

}

 

static int TX2440_ds18b20_open(struct inode *inode, struct file *file)

{

    printk("TX2440-DS18B20 Driver Open is Called!\n");

    DS18B20_TmpChange();

    mdelay(1000);

    DS18B20_Temperature();

    DS18B20_TmpChange();

    mdelay(1000);

    DS18B20_Temperature();

    return 0;

}

 

static int TX2440_ds18b20_release(struct inode *inode, struct file *file)

{

    printk("TX2440-DS18B20 Driver Release Called!\n");

    return 0;

}

 

static int TX2440_ds18b20_read(struct file *filp, char *buf, size_t count, loff_t *f_pos)

{

    U16 ds18b20_val;

   

    DS18B20_TmpChange();

    mdelay(500);

    ds18b20_val =  DS18B20_Temperature();

    if (ds18b20_val < 10000)

        copy_to_user(buf, &ds18b20_val, sizeof(ds18b20_val));

   

    return 0;

}

 

static struct file_operations TX2440_ds18b20_fops =

{

    .owner  =   THIS_MODULE,

    .open   =   TX2440_ds18b20_open,

    .release =  TX2440_ds18b20_release,

//  .ioctl  =   TX2440_ds18b20_ioctl,

    .read   =   TX2440_ds18b20_read,

};

 

static struct class *ds18b20_class;

 

static int __init TX2440_ds18b20_init(void)

{

 

    printk("TX2440 DS18B20 DRIVER MODULE INIT\n");

 

    DS18B20_Init();  //DS18B20初始化

 

    DS18B20_Major = register_chrdev(0, DEVICE_NAME, &TX2440_ds18b20_fops);

    if (DS18B20_Major < 0)

    {

        printk(DEVICE_NAME " can't register major number\n");

        return DS18B20_Major;

    }

    printk("register TX2440-DS18B20 Driver OK! Major = %d\n", DS18B20_Major);

 

    ds18b20_class = class_create(THIS_MODULE, DEVICE_NAME);

    if(IS_ERR(ds18b20_class))

    {

        printk("Err: failed in TX2440-DS18B20 class. \n");

        return -1;

    }

 

    device_create(ds18b20_class, NULL, MKDEV(DS18B20_Major, 0), NULL, DEVICE_NAME);

 

    printk(DEVICE_NAME " initialized\n");

    return 0;

}

 

static void __exit TX2440_ds18b20_exit(void)

{

    printk("TX2440 DS18B20 DRIVER MODULE EXIT\n");

    unregister_chrdev(DS18B20_Major, DEVICE_NAME);

    device_destroy(ds18b20_class, MKDEV(DS18B20_Major, 0));

    class_destroy(ds18b20_class);

}

 

module_init(TX2440_ds18b20_init);

module_exit(TX2440_ds18b20_exit);

 

MODULE_AUTHOR("www.txmcu.com");    

MODULE_DESCRIPTION("TX2440 DS18B20 Driver"); 

MODULE_LICENSE("GPL");

 

源代码: TX2440_ds18b20.rar   

测试程序: ds18b20.rar   

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