DS1621温度传感器实验

/*************** writer:shopping.w ******************/

#include

#include

#define uint unsigned int

#define uchar unsigned char

bit I2C_Busy, NO_Ack,Bus_Fault,point;

uchar bdata a;

sbit LSB = a^0;

sbit MSB = a^7;

sbit SDA = P3^3;

sbit SCL = P3^2;

uchar Array[] = {'0','1','2','3','4','5','6','7','8','9'}; uchar command_data[]=

{

0xac,0x00,0xee,0xa1,0x00,0x00,0xa2,0x00,0x00,0xaa

};

uchar Prompt[]="Waiting for a while...\r";

uchar i;

void DelayMS(uint ms)

{

uchar i;

while(ms--)

{

for(i=0;i<120;i++);

}

}

void SendStop()

{

SDA = 0;

SCL = 1;

_nop_();

SDA = 1;

I2C_Busy = 0;

}

void SendByte(uchar wd)

{

uchar i;

a = wd;

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

{

SCL = 0;

_nop_();

_nop_();

SDA = MSB;

a <<= 1;

_nop_();

_nop_();

SCL = 1;

_nop_();

_nop_();

SCL = 0;

}

SDA = 1;

SCL = 1;

_nop_();

_nop_();

if(!SDA)

{

SCL = 0;

_nop_();

_nop_();

}

else

{

NO_Ack = 1;

SCL = 0;

_nop_();

_nop_();

}

}

void Master(uchar slave_addr) {

I2C_Busy = 1;

NO_Ack = 0;

Bus_Fault = 0;

if(!SCL || !SDA)

Bus_Fault = 1;

else

{

SDA = 0;

_nop_();

_nop_();

SCL = 0;

_nop_();

_nop_();

SendByte(slave_addr);

}

}

uchar RecvByte(uchar cnt)

{

uchar i,rcv_data;

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

{

SDA = 1;

SCL = 1;

_nop_();

LSB = SDA;

if(i<7)

a <<= 1;

_nop_();

SCL = 0;

_nop_();

}

if(cnt == 1)

SDA = 1;

else

SDA = 0;

SCL = 1;

_nop_();

SCL = 0;

SDA = 1;

_nop_();

rcv_data = a;

return rcv_data;

}

void SendData(uchar slave_address,uchar start,uchar end) {

Master(slave_address);

for(i=start;i<=end;i++)

SendByte(command_data[i]);

SendStop();

}

void InitialiseSerialPort()

{

TMOD = 0x20;

TH1 = 0xfd;

SCON = 0x50;

TR1 = 1;

}

void SendCharToSerialPort(uchar ch)

{

SBUF = ch;

while(!TI);

TI = 0;

}

void SendTemperatureToSerialPort(uchar val) {

if(val>200)

{

val = 255-val;

SendCharToSerialPort('-');

if(!point)

val+=1;

}

SendCharToSerialPort(Array[(val/10)/10]);

SendCharToSerialPort(Array[(val/10)%10]);

SendCharToSerialPort(Array[val%10]);

SendCharToSerialPort('.');

if(point)

SendCharToSerialPort('5');

else

SendCharToSerialPort('0');

SendCharToSerialPort(' ');

SendCharToSerialPort('C');

SendCharToSerialPort('\r');

}

void SetTemperatureLimit(uchar HI,uchar LO) {

command_data[4] = HI;

command_data[5] = 0;

command_data[7] = LO;

command_data[8] = 0;

SendData(0x90,3,5);

DelayMS(10);

SendData(0x90,6,8);

}

void StartConversion()

{

SendData(0x90,2,2);

DelayMS(750);

}

uchar ReadTemp()

{

uchar d;

SendData(0x90,9,9);

Master(0x91);

d = RecvByte(0);

point = RecvByte(1)>>7;

SendStop();

return d;

}

void WriteConfig(uchar c)

{

command_data[1] = c;

SendData(0x90,0,1);

}

void main()

{

uchar i;

InitialiseSerialPort();

while(Prompt[i]!='\0')

SendCharToSerialPort(Prompt[i++]);

WriteConfig(0x02);

StartConversion();

SetTemperatureLimit(40,35);

while(1)

{

DelayMS(50);

SendTemperatureToSerialPort(ReadTemp());

}

}