DS2431 DS18B20读写程序

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：

#include \"system.h\"

#include \"one wire.h\"

unsigned char a_DS2431[8];

//code by lyx and RyanHsiung

#define DS_DQ_IN PORTAbits.RA4

#define DS_DQ_OUT LATAbits.LATA4

#define DS_DQ_TRISD TRISAbits.TRISA4

void 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)

{

unsigned char bit0,cbit,r,temp,i,j,byte;

temp=0;

for (j=0;j{

byte=p[j];

for(i=0;i<8;i++)

{

cbit=temp&0x01;

bit0=byte&0x01;

temp=temp>>1;

r=cbit^bit0;

if(r==1)

temp=temp^0x8c;

byte=byte>>1;

}

}

return temp;

}

/*********************************************

检查DS1820是否存在：

如果DS1820不存在返回1，否则返回0

*********************************************/

unsigned 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);

delay_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;i<8;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 (i<7)

byte=byte>>1;

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DS1820

*********************************************/

void OneWire_write(unsigned char cmd)

{

unsigned char i,j;

DS_DQ_TRISD=0;//RE2输出

for (j=0;j<=7;j++)

{

i=cmd&0x01;

if (i==0x01)

{

DS_DQ_OUT=0;//输出LOW

delay_us(5);

DS_DQ_OUT=1;//输出HIGH

delay_us(120);

}

else

{

DS_DQ_OUT=0;//输出LOW

delay_us(120);

DS_DQ_OUT=1;//输出HIGH

delay_us(5);

}

cmd=cmd>>1;

}

}

/*********************************************

匹配DS1820

*********************************************/

void OneWire_match(unsigned char *p)

{

unsigned char i;

do

i=OneWire_ack();

while (i==0x01);

OneWire_write(0x55);

for(i=0;i<8;i++)

OneWire_write(p[i]);

}

uint8 DS2431_WriteOneByte(uint16 address, uint8 * p_data)

{

uint8 tem8h,tem8l,i,data,errors,temp8;

tem8h=(unsigned char)(address>>=4);

tem8l =(unsigned char)address;

if(OneWire_ack()) return;

OneWire_write(0xcc); //跳过ROM匹配

OneWire_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;i<8;i++)

{

data=*p_data;

p_data++;

OneWire_write(data);

// ClrWDT();

}

delay_us(25);

if(OneWire_ack()) return;

OneWire_write(0xcc); OneWire_write(0xAA); temp8=OneWire_read();

temp8<<=8;

temp8+=OneWire_read();

errors=OneWire_read(); if(errors!=0x07)

//跳过ROM匹配

//复制暂存器数据到存储器中

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<50;i++)

delay_us(100); //等待写时序结束 510us

if(OneWire_read()!=0xAA)

return 0;

return 1;

/*

unsigned char i=1;

if(OneWire_ack()) return;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0x0f); // write scrachpad

OneWire_write(0x20); // ta1

OneWire_write(0x00); // ta2

OneWire_write(data); // data

a_DS2431[0] = OneWire_read();

a_DS2431[1] = OneWire_read();

crccheck(a_DS2431,2);

*/

}

uint8 DS2431_WriteString(uint16 address, uint8 * p_data)

{

uint8 tem8h,tem8l,i,data,errors,temp8;

tem8h=(unsigned char)(address>>=4);

tem8l =(unsigned char)address;

if(OneWire_ack()) return;

OneWire_write(0xcc); //跳过ROM匹配

OneWire_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;i<8;i++)

{

data=*p_data;

p_data++;

OneWire_write(data);

}

delay_us(25);

if(OneWire_ack()) return;

OneWire_write(0xcc); OneWire_write(0xAA); temp8=OneWire_read();

temp8<<=8;

temp8+=OneWire_read();

errors=OneWire_read(); if(errors!=0x07)

return 0;

if(OneWire_ack()) return;

//跳过ROM匹配

//复制暂存器数据到存储器中

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<50;i++)

delay_us(100); //等待写时序结束 510us

if(OneWire_read()!=0xAA)

return 0;

return 1;

/*

unsigned char i=1;

if(OneWire_ack()) return;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0x0f); // write scrachpad

OneWire_write(0x20); // ta1

OneWire_write(0x00); // ta2

OneWire_write(data); // data

a_DS2431[0] = OneWire_read();

a_DS2431[1] = OneWire_read();

crccheck(a_DS2431,2);

*/

}

uint8 DS2431_ReadOneByte(uint16 address )

{

if(OneWire_ack()) return;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0xf0);//发出读存储器命令

OneWire_write(LS_BYTE(address) );//地址低8位

OneWire_write(HS_BYTE(address));//地址高8位

a_DS2431[0] = OneWire_read(); // read data

return a_DS2431[0];

/*

unsigned char i=1;

if(OneWire_ack()) return;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0xaa); //

a_DS2431[0] = OneWire_read(); // read ta1

a_DS2431[1] = OneWire_read(); // read ta2

a_DS2431[2] = OneWire_read(); // read es

a_DS2431[3] = OneWire_read(); //read data

a_DS2431[4] = OneWire_read(); //crc

a_DS2431[5] = OneWire_read(); //CRC

crccheck(&a_DS2431[4],2);

*/

}

uint8* DS2431_ReadString(uint16 address)

{

uint8 i;

if(OneWire_ack()) return;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0xf0);//发出读存储器命令

OneWire_write(LS_BYTE(address) );//地址低8位

OneWire_write(HS_BYTE(address));//地址高8位

for(i=8;i>0;i--)

{

a_DS2431[8-i]=OneWire_read();

// ClrWDT();

}

return a_DS2431;

}

void Start_convert_ds18b20(void)

{

unsigned 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 OneWire[9];//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 0x5fff;

OneWire_write(0xcc);//跳过ROM匹配

OneWire_write(0xbe); //读转换后温度值

for (i=0;i<9;i++)

{

OneWire[i]=OneWire_read();

}

OneWire_temp=OneWire[1];

OneWire_temp=OneWire_temp<<8;

OneWire_temp+=OneWire[0];

if ((OneWire_temp&0xf800)!=0)//判断是否小于0度

{

OneWire_temp=~OneWire_temp;

OneWire_temp++;

flag_temp=1;

}

OneWire_temp+=8; //四舍五入 8*0.0625=0.5 2k90717

OneWire_temp>>=4;

if(OneWire_temp>0) 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);

}