Arduino vs. graphical LCD

Forum 2005-2010 (read only) Hardware Interfacing
1

I was considering to use a graphical LCD in my next project.. but when I looked at the datasheets.. they don't have ANY built-in fonts.. which means you would have to build all of that functionality into the Arduino sketch or make a library from scratch..
In my Mouser catalog it had a page from DisplayTech which looks like decent size and price..
http://www.displaytech-us.com/products/graphicmodules.php

The display I was looking at has an 8 bit interface or serial interface (input only with clock) here: http://www.displaytech-us.com/pdf/FullSpecs/S32128A-v11.pdf

Do you think trying to initialize and maintain the display will consume too much overhead that I won't be able to do much else on the Arduino? I figure it would take at least 500k ROM just to have a full ASCII font set..
I was going to use the serial interface.. I haven't found a reason yet to need to read back from LCD Ram.. Is there one?

2

You could use the arduino EEPROM for your ascii library, saves space for your program

3

I can't think of any reason to need to read back from the LCD unless it has touch screen support, which I'm sure it doesn't.

If you use 8x8 fonts, you only need 2kb for a full 256 character font array; each character would be 8 bytes, stored as 1bit-per-pixel bitmap. If you decide not to use higher ascii values you can cut that to 1kb, and if you only want letters (upper and lowercase)+numbers and minor punctuation, you can cut even that in half, AND if you want to cut it back to just all uppercase and numbers with punctuation, you could fit it all into the 512bytes of eeprom.

I don't know how you got to 500kb for a full font set, unless you want some huge resolution fonts!

4

There is code to drive a graphic LCD in the Arduino playground that includes storing fonts in program memory. This library uses the ks0108 chip so you may want to search out for an LCD panel that uses this controller.

5

This sort of LCD display requires too much memory and processing power to be used with an Arduino. It requires a processor with a built in LCD driver to handle the refresh rate required, and a lot more memory with fast access.

6

500k.. oops.. I meant ~500 bytes (5 bytes for each character with roughly 100 characters)

The LCD above I was looking at has a built in LCD driver and handles refresh itself.. It says you can update the LCD ram without causing flicker because it buffers the data before displaying it.