/*************** writer:shopping.w ******************/
#include <reg52.h>
#include <intrins.h>
#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());
}
}。