温度传感器18B20驱动程序(C语言).doc

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1、温度传感器18B20驱动程序(C语言) /* *18B20驱动程序，DQ为数据口，接于P2.1 *11.0592M晶振，上拉4.7k电阻 *Author:fyb *2005-3-25 11:23，OK! */ i nclude i nclude #define uchar unsigned char #define uint unsigned int sbit dq = P17; bit flag; uint Temperature; uchar temp_buff9; /存储读取的字节，read scratchpad为9字节，read rom ID为8字节 uchar id_buff8; u

2、char *p; uchar crc_data; uchar code CrcTable 256= 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, 190, 224, 2, 92, 223, 129, 99, 61,

3、 124, 34, 192, 158, 29, 67, 161, 255, 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, 248, 166, 68, 26, 153, 199, 37, 123, 58, 10

4、0, 134, 216, 91, 5, 231, 185, 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 7

5、6, 18, 145, 207, 45, 115, 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84,

6、 215, 137, 107, 53; / /* *Function:延时处理 *parameter: *Return: *Modify: */ void TempDelay (uchar us) while(us-); /* *Function:18B20初始化 *parameter: *Return: *Modify: */ void Init18b20 (void) dq=1; _nop_(); dq=0; TempDelay(86); /delay 530 uS/80 _nop_(); dq=1; TempDelay(14); /delay 100 uS/14 _nop_(); _no

7、p_(); _nop_(); if(dq=0) flag = 1; /detect 1820 success! else flag = 0; /detect 1820 fail! TempDelay(20); /20 _nop_(); _nop_(); dq = 1; /* *Function:向18B20写入一个字节 *parameter: *Return: *Modify: */ void WriteByte (uchar wr) /单字节写入 uchar i; for (i=0;i= 1; /* *Function:读18B20的一个字节 *parameter: *Return: *Mo

8、dify: */ uchar ReadByte (void) /读取单字节 uchar i,u=0; for(i=0;i= 1; dq = 1; if(dq=1) u |= 0x80; TempDelay (4); _nop_(); return(u); /* *Function:读18B20 *parameter: *Return: *Modify: */ void read_bytes (uchar j) uchar i; for(i=0;ij;i+) *p = ReadByte(); p+; /* *Function:CRC校验 *parameter: *Return: *Modify:

9、 */ uchar CRC (uchar j) uchar i,crc_data=0; for(i=0;ij;i+) /查表校验 crc_data = CrcTablecrc_datatemp_buffi; return (crc_data); /* *Function:读取温度 *parameter: *Return: *Modify: */ void GemTemp (void) read_bytes (9); if (CRC(9)=0) /校验正确 Temperature = temp_buff1*0x100 + temp_buff0; / Temperature *= 0.625; T

10、emperature /= 16; TempDelay(1); /* *Function:内部配置 *parameter: *Return: *Modify: */ void Config18b20 (void) /重新配置报警限定值和分辨率 Init18b20(); WriteByte(0xcc); /skip rom WriteByte(0x4e); /write scratchpad WriteByte(0x19); /上限 WriteByte(0x1a); /下限 WriteByte(0x7f); /set 11 bit (0.125) Init18b20(); WriteByte(0

11、xcc); /skip rom WriteByte(0x48); /保存设定值 Init18b20(); WriteByte(0xcc); /skip rom WriteByte(0xb8); /回调设定值 /* *Function:读18B20ID *parameter: *Return: *Modify: */ void ReadID (void)/读取器件 id Init18b20(); WriteByte(0x33); /read rom read_bytes(8); /* *Function:18B20ID全处理 *parameter: *Return: *Modify: */ void TemperatuerResult(void) p = id_buff; ReadID(); Config18b20(); Init18b20 (); WriteByte(0xcc); /skip rom WriteByte(0x44); /Temperature convert Init18b20 (); WriteByte(0xcc); /skip rom WriteByte(0xbe); /read Temperature p = temp_buff; GemTemp();