hej cheater, great idea! just 2 questions: do you target a special LCD or is your board supposed to be a general garphics card?
This is designed for a standard HD44780 character LCD, not a graphical one.
The idea however can be adapted to nearly anything.
i'm asking this, because i use these monochrome nokia displays (monochrome, 84px x 48px). i have the code working and really would like to work on a library if someone would be willing to assist. the problem with this display is, that it works on 3.3v and comes with a pretty annoying connector which like cries for a custom board.
I'd assist if I had one.
my second question is a general question on your first design. do you (or anyone) have experience on running an atmega on the internal oscillator at 8Mhz? just maybe you don't need the crystal and can save that space. if the communication uses a clock line i wouldn't see a problem with timing or speed. what do think?
I dont have experience with it but I have ordered a bunch of ATtiny chips to play with along with two ATmega32's.
So in a week or two I will have experience running them without a crystal.
Space isnt a issue with my design.
The width is constant because I want it to fit in a DIP socket and the length is also constant because it needs to match a LCD's pin out.
The crystal is dirt cheap and is faster and more reliable. Why not have it?
For smaller designs I probably wouldnt have one though.
as for a backlight transistor: i think bc-337 and 2n2222 would be suited. at least these i've found to meet very often, and if i remember correctly support a max of 400mA (or was it 800?).
I found a SMD one which says its max current is 800mA so that should be fine.
The backlight shouldnt cause much of a problem anyway.
I've got a neat setup where I control 4 20x4 LCDs from three pins with individual backlight control.
A 595 can power the backlights just fine even with massive capacitors which make a cool fading effect.
if we could find a reasonable priced way to get them here to berlin, i'd be interested in at least 2 of these :-)
Australia to Berlin should be fine.
I'm getting a 128x64 graphical LCD (a larger one, not a tiny one. KS0108B controller) so I can definitely help with graphical routines for any LCD and a library for similar LCDs.
Just need to dust off my trigonometry.
I could also make a backpack or shield for other LCDs which does all the hard work and provides Serial/I2C/SPI interfaces.
Making one for a PSP LCD (with touch screen even) would be bloody cool.