(vii) Learning AD conversion for ADC0809 analog-to-digital conversion

ADC0808

Pin function each pin function is as follows:

26~28 (in0~in7): 8 Analog inputs 8, 14, 15 and 17~21:8 bits digital output (ALE): Address latch allows signal, input, high active. 6 (START): A/D conversion start pulse input, input a positive pulse (at least 100ns wide) to enable it to start (pulse rising edge to make 0809 reset, falling edge to start A/D conversion). 7 (EOC): A/D conversion end signal, output, when the A/D conversion ends, this end outputs a high level (always low during conversion).    9 (OE): Data output allows signal, input, high active. At the end of the A/D conversion, this terminal inputs a high level and outputs a digital quantity. (CLK): clock pulse input. Requires a clock frequency of not more than 640KHZ. (Vref (+)) and (Vref (-)): Reference voltage input 23~25 (ADDA, ADDB, ADDC): 3-bit address input line for the one-way simulation in the 8-channel analog input: Calculation formula: 3.45/5= x/255 then x=175.95 is 176 (corresponding to the LED 1011 0000), the experiment correctly refer to the program code:

1#include <reg52.h>2 #defineUchar8 unsigned char3 #defineuint16 unsigned int4 #defineLED P05 #defineOut P16Sbit start = p2^1 ;7Sbit OE = p2^7;//at the end of the A/D conversion, this terminal inputs a high level and outputs a digital quantity. oe=0, turn off output, no output to single chip microcomputer8Sbit EOC = p2^3;//A/D conversion end signal, output, when the A/D conversion ends, this end outputs a high level (the conversion period has been low). 9Sbit CLOCK = p2^0;//clock-Pulse inputTen  OneSbit add_a = p2^4;//ABC is used to select the channel of the ADC chip, ASbit add_b = p2^5; -Sbit Add_c = p2^6; -  the voidMainvoid) - { -  - Uchar8 temp; +  -Add_a=0; add_b=0; Add_c=1;//Select the ADC0809 chip Channel 4 corresponds to +  A    while(1) at   { -start=0; -start=1;//Rising edge makes 0809 reset -start=0;//Falling edge start ad conversion -        -        while(1) in       { -CLOCK =! CLOCK;if(EOC = =1) Break;//wait for the transition to end, jump out of the loop to       } +         -Oe=1; the  *temp = out;//Staging Conversion Results $OE =0;//Turn off outputPanax Notoginseng  -Led=~temp;//This is the reverse, because I have the wiring of the circuit. the                       //so through the software modification, so that the LED light is 1, out of 0 +                         //sample results are output to LED lights via P0 Port A   } the  +}

Summary: How to expand the display on the digital tube or LCD screen display it?????? A bit difficult, can't think of, there is no special decoder????

(vii) Learning AD conversion for ADC0809 analog-to-digital conversion