[SOLVED] Issues in Lcd interfacing with 8051

[Akshit Sharma]

Hi,
I am interfacing a 16x2 LCD with AT89c51 microcontroller. Attached is the design file and c code for the same. I am getting a logic contention warning on proteus. I have checked my code many times but couldn't find anything. Please Help.
Thanks
code

#include <reg51.h>
sbit rs=P2^5;
sbit rw=P2^6;
sbit en=P2^7;
sbit busy=P3^7;
void lcdcmd(unsigned char);
void lcddata(unsigned char);
void lcdready();
void delay();
void main()
{
	lcdcmd(0x38);
	lcdcmd(0x0C);
	lcdcmd(0x01);
	lcdcmd(0xC0);
	lcddata('H');
	lcddata('I');
	while(1);
}
void lcdcmd(unsigned char value)
{
	lcdready();
	P3=value;
	rs=0;
	rw=0;
	en=1;
	delay();
	en=0;
}
void lcddata(unsigned char value)
{
	lcdready();
	P3=value;
	rs=1;
	rw=0;
	en=1;
	delay();
	en=0;
}
void lcdready()
{
	busy=1;
	rw=1;
	rs=0;
	while(busy==1)
	{
		en=0;
	  delay();
	  en=1;
	}
}
void delay()
{
	unsigned int j;
  for(j=0;j<2550;j++);
}

 

[jayanth.devarayanadurga]

Pins connected to LCD are not configured as output pins.

 

[Akshit Sharma]

Pins connected to LCD are not configured as output pins.

I have tried the same program using my name as the string. It works fine till AKS (in image below) but after that i get a logic contention. I tried configuring the port as output using 0x00 but still get the same error. If there's some other method, please let me know. Thanks

 

[jayanth.devarayanadurga]

Zip and post project files + Proteus file.

 

[Akshit Sharma]

Zip and post project files + Proteus file.

Here is the file. Thanks and tell me if you require any other file. View attachment lcd.rar

 

[jayanth.devarayanadurga]

Try this code...

 

[Akshit Sharma]

Try this code...

This code works fine even if i don't use p3=0x00; and p2=0x00; but the main purpose of using the busy bit is defeated. I was trying to get the busy bit into action. Can't i use the busy bit and get it going as well? Thanks.

- - - Updated - - -

I rearranged the original code a little by using P3=value after initializing RW and RS in both lcddata and lcdcmd functions. This reduced the number of logic contentions. But i still get one logic contention if I try writing anything after 'H' in the wire connecting D2 of LCD. Thanks

- - - Updated - - -

Problem solved. I used P3=0xFF i place of using busy=1 in lcdready() and the error was gone. Thanks for the help.