DS2431 DS18B20读写程序(7页).doc

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1、-DS2431 DS18B20读写程序-第 7 页DS2431 DS18B20 one wire 读写程序最近公司有一个产品用到了DS2431,我就将先前一个DS18B20的程序中加入了DS2431的按规定函数。先传给大家分享.大家可以使用，转载时请说明出处. 此程序不够完善，希望能支持多节点设备连接。单总线适用于单主机系统，能够控制一个或多个从机设备。主机可以是微控制器，从机可以是单总线器件，它们之间的数据交换只通过一条信号线。当只有一个从机设备时，系统可按单节点系统操作；当有多个从机设备时，系统则按多节点系统操作。 以下是程序：#includesystem.h#includeone wir

2、e.hunsigned char a_DS24318;/code by lyx and RyanHsiung#define DS_DQ_IN PORTAbits.RA4#define DS_DQ_OUT LATAbits.LATA4#define DS_DQ_TRISD TRISAbits.TRISA4void delay_us(unsigned char time) /delayms=1us of 20Mhz osc /不准确1us while(time-); CRC校验unsigned char crccheck(unsigned char *p,unsigned char len)uns

3、igned char bit0,cbit,r,temp,i,j,byte;temp=0;for (j=0;jlen;j+) byte=pj; for(i=0;i1; r=cbitbit0; if(r=1) temp=temp0x8c; byte=byte1;return temp; 检查DS1820是否存在：如果DS1820不存在返回1，否则返回0unsigned char OneWire_ack(void) unsigned char ack; DS_DQ_TRISD=0; /输出 DS_DQ_OUT=0; /输出LOW /delay_us(500); delay_us(250); dela

4、y_us(250); delay_us(100); DS_DQ_OUT=1;/输出HIGH DS_DQ_TRISD=1;/RE2输入 delay_us(40);/delay_us(45); if(DS_DQ_IN=1) ack=1; / else ack=0;/ /delay_us(500); delay_us(250); delay_us(250); delay_us(100); return ack; 从DS1820读1字节数据unsigned char OneWire_read(void) unsigned char i,byte,temp; byte=0x00; for (i=0;i8

5、;i+) DS_DQ_TRISD=0;/RE2输出 DS_DQ_OUT=0;/输出LOW delay_us(1);/delay_us(3); DS_DQ_OUT=1;/输出HIGH DS_DQ_TRISD=1;/RE2输入 delay_us(5);/delay_us(10); if(DS_DQ_IN) byte|=0x80; / 读入 if (i1; delay_us(120);/delay_us(100); DS_DQ_TRISD=0;/RE2输出 delay_us(2);/delay_us(5); return byte; 写ROM或存贮器命令到DS1820void OneWire_wri

6、te(unsigned char cmd) unsigned char i,j; DS_DQ_TRISD=0;/RE2输出 for (j=0;j1; 匹配DS1820void OneWire_match(unsigned char *p) unsigned char i; do i=OneWire_ack(); while (i=0x01); OneWire_write(0x55); for(i=0;i=4);tem8l =(unsigned char)address; if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_wr

7、ite(0x0f);/发送写暂存器命令OneWire_write(tem8l);/发送地址低位OneWire_write(tem8h);/发送地址高位 for(i=0;i8;i+)data=*p_data;p_data+;OneWire_write(data);/ClrWDT();delay_us(25); if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0xAA); /复制暂存器数据到存储器中temp8=OneWire_read();temp8=8;temp8+=OneWire_read();errors=O

8、neWire_read(); if(errors!=0x07)return 0; if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0x55);/发出启动转换命令OneWire_write(tem8l);/发送地址低位OneWire_write(tem8h);/发送地址高位 OneWire_write(errors);for(i=0;i=4);tem8l =(unsigned char)address; if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配One

9、Wire_write(0x0f);/发送写暂存器命令OneWire_write(tem8l);/发送地址低位OneWire_write(tem8h);/发送地址高位 for(i=0;i8;i+)data=*p_data;p_data+;OneWire_write(data);delay_us(25); if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0xAA); /复制暂存器数据到存储器中temp8=OneWire_read();temp8=8;temp8+=OneWire_read();errors=OneW

10、ire_read(); if(errors!=0x07)return 0; if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0x55);/发出启动转换命令OneWire_write(tem8l);/发送地址低位OneWire_write(tem8h);/发送地址高位 OneWire_write(errors);for(i=0;i0;i-)a_DS24318-i=OneWire_read();/ClrWDT();return a_DS2431;void Start_convert_ds18b20(void)uns

11、igned char i=1; if(OneWire_ack() return;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0x44); /启动DS1820转换unsigned int Read_convert_ds18b20(unsigned char flag_language)unsigned char i;unsigned char OneWire9;/存放从DS18B20读取的9字节数据unsigned int OneWire_temp;unsigned char flag_temp=0;if(OneWire_ack() return 0x5f

12、ff;OneWire_write(0xcc);/跳过ROM匹配OneWire_write(0xbe); /读转换后温度值for (i=0;i9;i+) OneWirei=OneWire_read();OneWire_temp=OneWire1; OneWire_temp=OneWire_temp=4; if(OneWire_temp0) OneWire_temp-; if(flag_language!=0) OneWire_temp=OneWire_temp*9/5; if(flag_temp=1) if(OneWire_temp=32) OneWire_temp=OneWire_temp-32; else OneWire_temp=32-OneWire_temp; flag_temp=0; else OneWire_temp=OneWire_temp+32; OneWire_temp&=0x00ff; if(flag_temp=1) OneWire_temp|=0xff00; return(OneWire_temp);