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[51] interfacing lm35 with 8051 using adc0804 to display temp. In 2 seven-segment displays

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interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment display

Here I am using the lm35 temperature sensor with 8051 using adc0804 to display 2 digits temperature data in 2 seven segment display.

i coulnot find the error either in the circuit or the source code. can u plz help me out with correction in circuit and code in c language..?

Code: 
program:
#include<reg51.h>
#define adcport P1

sbit cs=P3^7;
sbit rd=P3^6;
sbit wr=P3^5;
sbit intr=P3^4;
sbit en1=P3^0;
sbit en2=P3^1;

void conv();
void read();
unsigned char adcvalue;


void main()
{

en1=1;
en2=1;
while (1)
{
conv();
read();

if(P1=0x06)
{P0=0x06;
P2=0x4f;}

if(P1=0x07)
{P0=0x06;
P2=0x66;
}

if(P1=0x08)
{
P0=0x06;
P2=0x6d;}

if(P1=0x09)
{
P0=0x06;
P2=0x07;}

if(P1=0x0a)
{
P0=0x06;
P2=0x6f;}

if(P1=0x0b)
{
P0=0x5b;
P2=0x06;}

if(P1=0x0c)
{
P0=0x5b;
P2=0x4f;}

if(P1=0x0d)
{
P0=0x5b;
P2=0x6d;}

if(P1=0x0e)
{
P0=0x5b;
P2=0x07;}

if(P1=0x0f)
{
P0=0x5b;
P2=0x6f;}

if(P1=0x10)
{
P0=0x4f;
P2=0x3f;}

if(P1=0x11)
{
P0=0x4f;
P2=0x5b;}

if(P1=0x12)
{
P0=0x4f;
P2=0x66;}

if(P1=0x13)
{
P0=0x4f;
P2=0x7d;}

if(P1=0x14)
{
P0=0x4f;
P2=0x7f;}

if(P1=0x15)
{
P0=0x66;
P2=0x3f;}

if(P1=0x16)
{
P0=0x66;
P2=0x5b;}

if(P1=0x17)
{
P0=0x66;
P2=0x66;}

if(P1=0x18)
{
P0=0x66;
P2=0x7d;}

if(P1=0x19)
{
P0=0x66;
P2=0x7f;}

if(P1=0x1a)
{
P0=0x6d;
P2=0x3f;}

if(P1=0x1b)
{
P0=0x6d;
P2=0x5b;}

if(P1=0x1c)
{
P0=0x6d;
P2=0x66;}

if(P1=0x1d)
{
P0=0x6d;
P2=0x7d;}

if(P1=0x1e)
{
P0=0x6d;
P2=0x7f;}

if(P1=0x1f)
{
P0=0x7d;
P2=0x3f;}

}
}

void conv()
{
cs = 0;
wr = 0;
wr = 1; 
cs = 1; 
while (intr); 
}
	 
void read() 
{
cs = 0; //Make CS low
rd = 0; //Make RD low
adcvalue= adcport; //Read ADC port
rd = 1; //Make RD high
cs = 1; //Make CS high
}

the circuit image is attached, plz rectify me the error in circuit and the code.
if the code is wrong plz provide me the correct code to the circuit. IMG-20180601-WA0004.jpg
 
Last edited by a moderator:

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

All 'if' conditions should have ==, not =
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Hi,

you don´t provide an error description, thus we don´t know what´s going wrong. This makes helping difficult.
Please add some documentation to your code.

It seems you didn´t try to do a forum search for your problem.
There are a lot of discussions about C51, ADC0804 and LM35.
Just see the box below "Similar threads"

Klaus
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Hello,


is it a LM35DZ ? 10mV/°C 0 °C -> 0mv 20°C -> 200mV
With 8 bits resolution 256 points for 5000mV
you will get only +-2°C per points

you can use a switch() case function instead of a lot of if

Code: 
switch(p1)
{
  case 6 :
    {
       P0=0x06;
       P2=0x4f;
       break;
      }
case 7: 
  {
      P0=0x06; 
      P2=0x66;
      break;
    }
...etc
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Thank you for the response.

sir,

I didn't find the threads related to displaying the measured temperature on the 7 segment display.
The problem is tat whatever the change in temperature in the lm35dz, there is no change in the adc0804 output and the display on the 7 segments. The image which I have attached is same simulated in proteus with the c program.
plz rectify me, where the problem might have occured.
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Thank you for response

sir,

I have tried with the == in if condition, the warnings are cleared but there is no correct display in the 7 segments.
The output at adc0804 is same for all values of the temperature and the display too. What might be the problem ?
I am working on proteus software.
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Hi,

still we don´t have much chance to help, because you didn´t provide useful informations.

Give useful descriptions:
there is no change in the adc0804 output
Click to expand...
--> so please tell us what´s the ADC_ouptut.

there is no correct display in the 7 segments.
Click to expand...
--> tell us what the display shows.

simulated in proteus
Click to expand...
--> If you use a simulator, it should be easy for you to find out where the problem lies:
Just follow the signal flow:
* microcontroller generates the signals for the ADC --> ADC sends back conversion results --> microcontroller reads in conversion results --> microcontroller processes conversion results --> microcontroller generates the display signals --> microcontroller outputs the display signals --> display shows the result.

Work from left to right and check step by step if the values are as expected. (don´t go the the next step until the one before works as desired)
On the first mismatch try to debug it, if you don´t have success in debugging, then give us useful informations (Your debugging test: generated signals, expected signals, wrong signals).

Mind: We can only help you if you give use useful informations.

Klaus
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

I think if you go for some micro controller with built-in adc life will be easy.for example AT89c2051.
many years back I made it for 7-segment display.
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Hi,

True. Or a temperature sensor with digital interface. It will reduce hardware effort significantly...while improving noise, resolution, accuracy..

Klaus
 

Re: interfacing lm35 with 8051 using adc0804 to display temp. in 2 seven segment disp

Just use ICL7106 and there no microcontroller will be needed
 

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