2012年（1008）
分类：
2012-08-01 11:04:49
/************************************************
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 //读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里
}
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
