DS18B20 可编程数字温度计C程序.doc

附录二：18b20 C程序/将DQ与Vcc之间接入4.7K上拉电阻#include reg52.h#include INTRINS.H#include 1602.c#define uchar unsigned char#define uint unsigned int/#define CLEARSCREEN LCD_en_command(0x01) 1602清屏sbit DQ=P10;/*操作命令代码 跳过ROM 0xCC 发送温度转换 0xBE 写EEPROM 0x4E*/ /低层驱动子程序/void Init18B20(void); /初始化void Write18B20(uchar ch);/写数据unsigned char Read18B20(void);/读数据 void Delay15(uchar n); void Delay10ms(uint delay_num);void Display(void);/ code uchar decimalH=00,06,12,18,25,31,37,43,50,56,62,68,75,81,87,93;code uchar decimalL=00,25,50,75,00,25,50,75,00,25,50,75,00,25,50,75;uint ResultTemperatureH ,ResultTemperatureLH,ResultTemperatureLL;/整数,小数高位,小数低位uint ResultSignal;/符号位main() uint TemH,TemL,delay,k=0; for(; ; ) Init18B20(); Write18B20(0xCC);/跳过ROM _nop_(); /Write18B20(0x4E);/写EEPROM / Write18B20(0x00);/Th /Write18B20(0x00);/Tl Write18B20(0x7f);/12 bits温度分辨率 Init18B20(); Write18B20(0xCC);/跳过ROM _nop_(); Write18B20(0x44);/发送温度转换指令 Delay10ms(25); Delay10ms(25); Delay10ms(25); Delay10ms(25);/等待1s转换 Init18B20(); Write18B20(0xCC);/跳过ROM Write18B20(0xBE);/发送温度转换指令 TemL=Read18B20(); /读低位温度值 TemH=Read18B20(); /读高位温度值 Delay10ms(2); TemH=(TemH4); TemL=TemL&0x0f; /取低4位 if(TemH&0x80) TemH=TemH; TemL=TemL+1; ResultSignal=1; /负 else ResultSignal=0; /正 ResultTemperatureLH=decimalHTemL; ResultTemperatureLL=decimalLTemL; ResultTemperatureH=TemH; Display(); for(delay=0;delay60000;delay+); for(delay=0;delay20000;delay+); void Display(void) uint i,j,q; LCD_init(); CLEARSCREEN; LCD_en_command(0x01); delay_nms(2); q=ResultTemperatureH/100; i=(ResultTemperatureH%100)/10; j=ResultTemperatureH-(i*10+q*100); LCD_write_string(0,LINE1, Jaq1217 18B20 );if(ResultSignal) LCD_write_string(0,LINE2, T is:- . ); else LCD_write_string(0,LINE2, T is:+ . ); LCD_write_char(0x07,LINE2,q|0x30); LCD_write_char(0x08,LINE2,i|0x30); LCD_write_char(0x09,LINE2,j|0x30); LCD_write_char(0x0b,LINE2,(ResultTemperatureLH/10)|0x30);LCD_write_char(0x0c,LINE2,(ResultTemperatureLH%10)|0x30);LCD_write_char(0x0d,LINE2,(ResultTemperatureLL/10)|0x30);LCD_write_char(0x0e,LINE2,(ResultTemperatureLL%10)|0x30); unsigned char Read18B20(void) unsigned char ch; unsigned char q ; for(q=0;q1; DQ=0; _nop_(); DQ=1; _nop_();_nop_();_nop_();_nop_(); if(DQ=1) ch=ch|0x80; else ch=ch&0x7f; Delay15(3); DQ=1; return (ch); void Write18B20(uchar ch) uchar i; for(i=0;i1; _nop_(); void Init18B20(void) DQ=0; Delay15(33);/至少延时480us DQ=1; Delay15(10);/至少延时100us /*if(DQ=1) return 0; /初始化失败 else return 1;DQ=1; Delay15(18); */ void Delay15(uchar n) do _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_();