Hi Craig thank you very much for your reply,
You said you have it working under Keil. What is it failing under? A compiler from some other vendor or in assembly language?

I was rfefering to my 4 bit LCD routines which worked pretty well in one of the earlier project where LCD was connected directly to micro port pins in 4 bit mode.

When I tried to port the same code this time for the lcd connected to '541 with the scheme mentioned in earlier posts it started giving problems. I was using the following sequence for writing to LCD.

1. Enable the '541.
2. Set or CLear the RS line.
3. Put the upper 4 bit data/command onto the buffer.
4. Set EN.
5. Clear EN.
4. Put the lower 4 bit data/command onto the buffer.
4. Set EN.
5. Clear EN.

There were suffucient time delays in between the operations to satisfy the LCD timing requirements. Now I have modified the code as per your sugeestions in earlier post.

1. Enble '541.
2. Put the upper 4 bit along with proper RS value and EN high.
3. Put the upper 4 bit along with proper RS value and EN low.
4. Put the lower 4 bit along with proper RS value and EN high.
5. Put the lower 4 bit along with proper RS value and EN low.

Of course there are sufficient delays for meeting timing specifications.

Now the modified code is working absolutely fine. Unfortunately I am away from my PC where I have all the source libraries I use. I am currently using my clients PC I had brought the code here and went on modifying it thus cant show you the old code at present however here is the modified and working code.

Regards,
Prahlad Purohit