Andy0613
87 lines
1.4 KiB
C
87 lines
1.4 KiB
C
#include "ds18b20.h"
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void DS18B20_Reset(void)
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{
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uchar i;
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DS18B20_DQ = 0;
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for(i=0; i<200; i++);
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DS18B20_DQ = 1;
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for(i=0; i<100; i++);
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}
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void DS18B20_WriteByte(uchar dat)
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{
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uchar i, j;
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for(i=0; i<8; i++)
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{
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DS18B20_DQ = 0;
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_nop_();
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if(dat & 0x01)
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DS18B20_DQ = 1;
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else
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DS18B20_DQ = 0;
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for(j=0; j<30; j++);
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DS18B20_DQ = 1;
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_nop_();
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_nop_();
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dat >>= 1;
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}
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}
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uchar DS18B20_ReadByte(void)
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{
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uchar i, j, dat = 0;
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for(i=0; i<8; i++)
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{
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dat >>= 1;
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DS18B20_DQ = 0;
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_nop_();
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DS18B20_DQ = 1;
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_nop_();
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_nop_();
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if(DS18B20_DQ)
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dat |= 0x80;
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for(j=0; j<20; j++);
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}
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return dat;
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}
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void DS18B20_StartConvert(void)
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{
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DS18B20_Reset();
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DS18B20_WriteByte(0xCC);
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DS18B20_WriteByte(0x44);
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}
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void DS18B20_SetResolution(uchar res)
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{
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// res: 0x1F=9bit, 0x3F=10bit, 0x5F=11bit, 0x7F=12bit
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DS18B20_Reset();
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DS18B20_WriteByte(0xCC); // Skip ROM
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DS18B20_WriteByte(0x4E); // Write Scratchpad
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DS18B20_WriteByte(0x00); // TH (user byte 1)
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DS18B20_WriteByte(0x00); // TL (user byte 2)
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DS18B20_WriteByte(res); // Configuration register
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DS18B20_Reset();
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DS18B20_WriteByte(0xCC); // Skip ROM
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DS18B20_WriteByte(0x48); // Copy Scratchpad to EEPROM
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}
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bit DS18B20_GetTemp(int *temp)
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{
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uchar tempL, tempH;
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int raw;
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DS18B20_Reset();
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DS18B20_WriteByte(0xCC);
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DS18B20_WriteByte(0xBE);
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tempL = DS18B20_ReadByte();
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tempH = DS18B20_ReadByte();
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raw = (tempH << 8) | tempL;
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*temp = raw;
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return 1;
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}
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