NXP 8051 – DC Motor Interfacing

[posie]

 

Hello friends..

 

I’m using NXP p89v51rd2 micro-controller. I want to run two 12v DC motors for which I’m using L293D driver.

 

I’m actuating the motors using data sent via serial port.. i.e Both the motors to run simultaneously when I send a character ‘S’ through serial port and stop when I send a character ‘R’.

 

This is my code :

 

 

#include <intrins.h>

#include “p89v51rx2.h”

 

sbit motora=P2^0;

sbit motorb=P2^1;

char getCharacter (void);    

 

void main (void)

{

char chr;

SCON = 0x50;

TMOD = 0x20;

TH1  = 0xFD;

TR1  = 1;

T1=1;

while(1)

{

chr = getCharacter ();

if (chr == ‘S’)

{

motora=1;

motorb=0;

}

else if(chr == ‘R’)

{

motora=0;

motorb=0;

}

 

}

}

 

char getCharacter (void)

{

       char chr;

       while (RI != 1) {;}

chr = SBUF;

RI = 0;

       return(chr);

}

 

The problem is when I send ‘S’ though the terminal…the two motor are moving just a single step (as if its a stepper motor )

 

Just a single step… and when I send ‘S’ again..it moves another step..

 

I used Vs = 12v (Motor voltage) from the Micro-Controller Development board…Is that the problem ??

 

What might be the issue ???

[AJISH ALFRED]

Hi,

please share your schematic also, it could happen due to hardware issues sometimes.

[matrixworld20]

when u send ‘s’ then only your loop is activated  for a moment after that both if loop not getting any code so it does not working,,,, u can check it by pressing ‘s’ countineusly..

 

sory for poor english

[matrixworld20]

 

status=1;

while(1)

{

chr = getCharacter ();

if (chr == ‘S’)

{

status=0;

}

if (chr == ‘R’)

{

status=1;

}

 

//====================================

if(status==0)

{

motora=1;

motorb=0;

}

 

if(status==1)

{

motora=0;

motorb=0;

}

 

 

 

and imp , u should have seperate the power source for both…  bcoz motor shrink more current probably it will damage controller

[Author]

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