how? 2 wire lcd with pbp?

[Melanie]

I assume you successfully initialised your LCD to work in 4-bit mode before throwing data at it?

[nimonia]

do i haf to always shift out 6 "0"s b4 sending every instruction set? how long do i ahf to pause b4 sending the next instruction?

[Luciano]

Hi,

What about I2C?

* * *

Nuts & Volts Column #109 May 2004 by Jon Williams:

Easy IO – Easy LCD Terminal
(I2C to LCD + Pushbuttons).

http://www.parallax.com/dl/docs/cols.../col/nv109.pdf
http://www.parallax.com/dl/docs/cols...code/nv109.zip

Microchip MCP23016 16-Bit I2C™ I/O Expander
http://ww1.microchip.com/downloads/e...Doc/20090b.pdf

Luciano

[Melanie]

Actually I just LOVE the MCP23008 from Microchip... you could do it with that too (using LCD 4-bit mode)...

I find that the skinny DIP (16F876/P type) is a nice economic package... but sometimes you just plain run out of I/O's... the 40-pin plastic package (16F877/P) takes up far too much real-estate and additional expense, so adding I/O's with the MCP23008 or 20016 is a very easy and neat solution - and they've got weak pull-up's too! Just perfect for remote Keypad/Display interface applications.

There's a lot of ways you can do LCD down two wires... (the obvious is to put a PIC at the LCD end), but at only a few cents for the package, the 74LS174 method (strictly it's 3-wires if you count Ground) has to be the rock-bottom cheapest.

PS... nimonia... use the same timing as PBP's LCD defines.

[Acetronics2]

Hi, nimonia

Devantech sells a ready to use I2C LCD ...

Here, for example :
http://www.robopolis.com/produit/156...I2C--serie.php

or Here : http://www.robot-electronics.co.uk/s..._LCD022058.htm

sooooooo easy.

Alain

[Demon]

"adding I/O's with the MCP23008 or 20016 is a very easy and neat solution"

Melanie is referring to the MCP23016, in case anyone is trying to find a 20016.

I agree, I'm in love with the MCP23008/16 chip (8 and 16 I/O pins). It's an awesome way to increase I/O pins on older chips like the 16F628 (a good strong and proven workhorse if you ask me).

The 16F877 is better, but at a cost. If you don't need more I/O pins AND extra memory, then it's overkill in a lot of applications.

Robert

[sougata]

Hi,

This is a serial LCD using a PIC. It takes commands in the LCDOUT style, hence is easy to incorporate.

Regards

Sougata