用C51写的AD7705

#include<reg51.h> #include<absacc.h> #include<intrins.h> #include<math.h> //#include<3310.h> sbit D_DAT=P1^0; //这一段是用来指定数显的，我用的是周立功dp-51开发机,该开发机有4个数码管 sbit D_CLK=P1^1; sbit DISPB0=P1^7; sbit DISPB1=P1^6; sbit DISPB2=P1^5; sbit DISPB3=P1^4; sbit DISPB4=P1^3; sbit ADC_DIN=P3^0; //这一段是指定ad7705的信号引脚 sbit ADC_CLK=P3^1; //指定时钟引脚 sbit ADC_DRDY=P3^2; //指定转换标志位 float voltage; //这个全局变量是用来给数显子程序传递采样到的数据的 unsigned char data display_buffer[5]; //显示缓冲 unsigned char code led[17]= //显示段码表 {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E,0xFF}; /*****************************************/ void send(unsigned char a) //通过P1口给数显发送8位数据 { unsigned char i; for(i=0;i<8;i++) { if(_crol_(a,i)&0x80) D_DAT=1; else D_DAT=0; D_CLK=0; D_CLK=1; } } /*****************************************/ void DISP_DLEAY(void) //显示延迟子程序 { unsigned char i,j; for(i=0;i<10;i++) for(j=0;j<5;j++); } /*****************************************/ /*void disp(void) //给数码管发显示缓冲区的段码 { unsigned char a; a=0xff; send(a); //DISPB0=0; DISP_DLEAY(); //DISPB0=1; a=led[display_buffer[1]]; send(a); //DISPB1=0; DISP_DLEAY(); //DISPB1=1; a=led[display_buffer[2]]; send(a); //DISPB2=0; DISP_DLEAY(); //DISPB2=1; a=led[display_buffer[3]]; send(a); //DISPB3=0; DISP_DLEAY(); //DISPB3=1; a=led[display_buffer[4]]; send(a); //DISPB4=0; DISP_DLEAY(); //DISPB4=1; } *? /*****************************************/ void display() /*将数据转换成相应的段码， 并给显示缓冲区赋段码*/ { float y,z,x; x=voltage; x=x/10.0; y=modf(x,&z); display_buffer[1]=(unsigned char)z; x=10.0*y; y=modf(x,&z); display_buffer[2]=(unsigned char)z; x=10.0*y; y=modf(x,&z); display_buffer[3]=(unsigned char)z; x=10.0*y; y=modf(x,&z); display_buffer[4]=(unsigned char)z; /*disp(); disp(); disp(); disp(); disp();*/ } /****************************************************************/ unsigned char rearrange(unsigned char a) /*将8位数据a的顺序颠倒后赋给b。 因为串口发送顺序和ad7705的接收顺序刚好相反*/ { unsigned char i,b; b=a&0x01; for(i=1; i<8; i++) { b=b<<1; a=a>>1; b=b+(a&0x01); } return(b); } /****************************************************************/ void WriteToReg_ADC(unsigned char a) //通过串口给ad7705发送命令字a { SCON=0; TI=0; SBUF=a; while(!TI); } /*************************************************************/ void MX7705_Init() //ad7705初始化 { unsigned char i; ADC_CLK=1; //防止接口迷失 ADC_DIN=1; for(i=0;i<100;i++)//prevent interface from losting { ADC_CLK=0; ADC_CLK=1; } WriteToReg_ADC(0x04); //write 0x20 to communication register to choose channel 0 //and clock register for the next one to write WriteToReg_ADC(0x20); //写0x04到时钟寄存器，指定晶振频率为2.4576MHz,采样率为50Hz. WriteToReg_ADC(0x08); //write 0x10 to communication register to choose channel 0 //and setup register for the next one to write WriteToReg_ADC(0x22); //写0x44到设置寄存器，指定增益为1, buffer off, FSYNC=0, and self-calibration } /*************************************************************/ unsigned int ReadWord() { unsigned char high8,low8; unsigned int out; SCON=0; REN=1; //allow serial port to recieve data RI=0; while(!RI); //waiting the end of recieve of 8 bit high8=SBUF; ADC_CLK=1; RI=0; while(!RI); low8=SBUF; REN=0; out=rearrange(high8); out=out<<8; out=out+rearrange(low8); return(out); } /*************************************************************/ /*************************************************************/ main() { unsigned int data_out; MX7705_Init(); while(ADC_DRDY==0) { WriteToReg_ADC(0x1C); //给通讯寄存器发0x38，指定下一个读数据寄存器 data_out=ReadWord(); //从数据寄存器中读16位数据 voltage=5.0*(data_out/65536.0); //将所读数据转换为电压值 display(); } }