[51] counter to display the count when 2Hz frequency is applied on on 3.5 port

[poojaghorpade]

Actually i want to display the count when 2Hz frequency is applied on 3.5 port of 89LV51....
Below i am attaching my code...
I am not getting output for code plz help me out .........

 

[BradtheRad]

How long do you open the time window to examine the incoming waveform?

2 Hz frequency means one cycle per 1/2 second. Therefore your code must watch the incoming signal for at least 1/2 second, to count one cycle.

The code does not need to watch uninterrupted all that time, but it needs to sample the incoming signal often enough so it can notice crests, troughs, zero transitions, etc.

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Also you need to make sure your signal's amplitude reaches a high enough and low enough voltage, so that your device recognizes its crests and troughs.

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Edited to change interrupted to uninterrupted, and to add last paragraph.

 

[poojaghorpade]

Have you gone through my attached file...

 

[BradtheRad]

I assumed your code is okay. I have no experience with microcontrollers or the programming language for the 89-51 series.

 

[andre_luis]

Once input reading is not being done through interrupt service, I believe the delay command you posted at line #27 - presumably scaled for 1s - could yield some problem:

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Code C - [expand]
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#include<reg51.h>
#include<stdio.h>
#include<string.h>
 
#ifdef reg51.h
 
sbit rs=P2^2;
sbit rw=P2^1;
sbit en=P2^0;
sbit busy=P0^7;
 
void lcdready();
int lcdcmd(unsigned int a);
int lcddata(unsigned char a);
int delay(unsigned int x);
int display(unsigned char);
void ascii(unsigned char value);
unsigned char msg[]={"counter"};
 
int lcdcmd(unsigned int a)
{
    lcdready();
    P0=a;
    rs=0;
    rw=0;
    en=1;
    delay(1);
    en=0;
    return;
}
 
int lcddata(unsigned char a)
{
lcdready();
    P0=a;
    rs=1;
    rw=0;
    en=1;
    delay(1);
    en=0;
    return;
}
 
void lcdready()
{
    busy=1;
    rs=0;
    rw=1;
    while(busy==1)
    {
        en=0;
        delay(1);
        en=1;
    }
    return;
}
 
int display(unsigned char msg[])
{
    unsigned char i=0;
    while(msg[i]!='\0')
    {
        lcddata(msg[i]);
        i++;
    }
    i=0;
    return;
}
    
 
int delay(unsigned int x)
{
    unsigned int i,j;
    for(i=0;i<=x;i++)
    {
        for(j=0;j<=125;j++)
    }
}
 
void main()
{
    lcdcmd(0x38);
    lcdcmd(0x0e);
    lcdcmd(0x01);
    lcdcmd(0x06);
    
    lcdcmd(0x80);
    display(msg);
    
    T1=1;
    TMOD=0x60;
    TH0=0;
    while(1);
    {
        do
        {
            TR0=1;
            value=TL0;
            ascii(value);
        }
        while(TF0==0);
        TR0=0;
        TF0=0;
    }
}
    
    
    void ascii(unsigned char value)
{
    unsigned char x,d1,d2,d3;
    x=value/10;
    d1=value%10;
    d2=x%10;
    d3=x/10;
    P0=30|d1;
    P1=30|d2;
    P2=30|d3;
}

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