PIC16F877A-SPI-TC77（温度传感器）

TC77：分辨率0.0625℃

#include

#define CS RC2

void initPORT();

void initMSSP();

void delay(unsigned char time);

void display(float data);

float ReadTC77();

const unsigned char disp[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

void main()

{

float temp;

initPORT();

initMSSP();

while(1)

{

temp=ReadTC77();

display(temp);

}

}

/*初始化PIC单片机端口*/

void initPORT()

{

TRISB=0x00; //控制段选

PORTB=0x00;

TRISC=0xf0; //与温度传感器连接

PORTC=0x00;

TRISA=0x00; //控制位选

PORTA=0xff;

}

/*初始化MSSP模块的SPI模式*/

void initMSSP()

{

SSPSTAT=0x00;

SSPCON=0x30;

SSPIF=0;

}

/*读取温度传感器的13位数值并且转换成浮点类型*/

float ReadTC77()

{

float result,PowerTwo=1;

unsigned char count,HighByte,LowByte;

CS=0;

SSPBUF=0;

while(!SSPIF){}

HighByte=SSPBUF; //获取温度寄存器的高字节

SSPIF=0;

SSPBUF=0;

while(!SSPIF){}

LowByte=SSPBUF; //获取温度寄存器的低字节

SSPIF=0;

CS=1;

for(count=0;count<8;count++) //转换整数部分

{

PowerTwo*=2;

if(HighByte&(0x01

}

PowerTwo=1;

for(count=0;count<5;count++) //转换个位及小数部分

{

if(LowByte&(0x80>>count)) result+=PowerTwo;

PowerTwo=PowerTwo/2.; //注意，不能换成.2，否则会出错

}

return result; //返回转换浮点结果

}

/*液晶显示*/

void display(float data)

{

unsigned int conver,First,Second,Third,Fourth;

conver=data*100;

First=conver/1000;

Second=conver/100%10;

Third=conver/10%10;

Fourth=conver%10;

PORTA=0xfe; //显示十位

PORTB=disp[First];

delay(2);

PORTB=0x00;

PORTA=0xfd; //显示个位

PORTB=0x80+disp[Second]; //加上0x80即可带点

delay(2);

PORTB=0x00;

PORTA=0xfb; //显示十分位

PORTB=disp[Third];

delay(2);

PORTB=0x00;

PORTA=0xf7; //显示百分位

PORTB=disp[Fourth];

delay(2);

PORTB=0x00;

}

void delay(unsigned char time)

{

unsigned char i,j;

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

for(j=255;j>0;j--);

}