51 single chip microcomputer - ADC0808 - 05 - ①

After all, ADC is a widely used and mature thing, and many things have been made, so I will use two or three experiments to describe this thing~

Let me first talk about the introduction of the ADC0808 A/D converter:

1. Introduction to ADC0808

An A/D converter is a circuit chip that can convert input analog voltage or current information into digital information proportional to it. An A/D converter is used to achieve the conversion from analog to digital.

ADC0808 is a typical 8-channel analog input 8-bit parallel digital output successive approximation A/D converter. The converter adopts CMOS technology and can realize time-sharing acquisition of 8 analog signals. There are 8 analog selection switches and corresponding channel address latch decoding circuits on the chip.

1) Introduction of ADC0808 chip

2) ADC0808 pinout

3) ADC0808 workflow

4) Interface with 51 MCU

Basically, that's all. It's very simple, right? I think so too.

Fuck, I spent a lot of time adjusting the program for nothing, just a little error, wasted a lot of time, it's really frustrating~~~

Check out the pictures~~

Since modular programming will be used in the future, it will be convenient for me to call it directly in the future~~~ , this main function:

//------------------------------------------------------------------------------
//Realize the voltage test of the resistor by using ADC0808 as an A/D converter
//The data range of the digital tube display is 0~255
#include"reg52.h"
#include"macroandconst.h"
#include"delay.h"
#include"adc0808.h"
//------------------------------------------------------------------------------
uchar code seg_disp[4]={0x10,0x20,0x40,0x00};   //LED display control code
uchar count;           //LED display bit control
sbit   tem=P2^0;
uchar temp_0=0;
//------------------------------------------------------------------------------
//Timer initialization function
void timer_init()
{
 TMOD=0X12;           //T0 works in mode 2, T1 works in mode 1
 TH0=(256-50)/256;
 TL0=TH0;
 TH1=(65536-4000)/256;
 TL1=(65536-4000)%6;

    ET0=1;
 ET1=1;
 TR0=1;
 TR1=1;
//  PT1=1;

 EA=1; 
}
//---------------------------------------------- ----------------------------------
//main
void main()
{
 timer_init();
 while(1 )
 {
  ADC0808_init();
 }
}
//---------------------------------------- -------------------------------------
//timer0
void timer0() interrupt 1
{
 CLK= ~CLK;
 if(temp_0==100)
 {
  temp_0=0;
  tem=~tem;
 }   
}
//-------------------------- -------------------------------------------------- --
//timer1
void timer1() interrupt 3
{
 TH1=(65536-4000)/256;
 TL1=(65536-4000)%6;
 for(count=0;count<4;count++)
 {
  P1=seg_disp[count ]|display[count];
  delay(10);
 }     
}   

Then comes the initialization function of ADC0808 (I won’t post some auxiliary functions, such as macro definition, software delay, pin definition, etc.):

//------------------------------------------------------------------------------
//file function of adc0808
#include "reg52.h"
#include "delay.h"
#include "macroandconst.h"
//------------------------------------------------------------------------------
sbit START=P3^0;         //conversion start signal
sbit OE=P3^1;         //output enable signal
sbit EOC=P3^2;         //conversion end status signal
sbit CLK=P3^7;         //clock signal input terminal, there is no clock circuit inside ADC0808, the required clock signal is input from the outside, usually the frequency is 500KHz
uchar get_data;         //ADC0808 converted value
uchar temp;          //used to store temporary value in the post-conversion processing of ADC0808
uchar display[3];        //store decimal value
//------------------------------------------------------------------------------
//ADC0808 startup and conversion initialization function
void ADC0808_init()
{
 START=0;           //START signal rising edge, clear all internal registers to 0
 START=1;           
 START=0;         //The falling edge of the START signal starts the A/D conversion. During the conversion process, START remains at a low level.

 while(EOC==0);        //Wait for the conversion to end

 OE=1;          // Allow the device to output the conversion result

 get_data=P0;        //P0 port connects to ADC0808, you know~~
 temp=get_data;        //temporarily store the conversion result

 OE=0;

 display[0]=get_data/100;     //Convert the result to decimal number
 display[1]=get_data0/10;
 display[2]=get_data;
}