GLCD - Could be fun

[George Sephton]

Im thinking of linking my PICAXE with a GLCD - In particular the TX36D86VC1CAA. Anyone done that before? Could be fun to see what we can do. Size 1024x768 nicked from an old laptop. I dont know the power but it say high voltage on it and im not sure what drivers it has already but the result comes to quite a lot of pins on a ribbon cable.

 

[hippy]

It's unlikely any PICAXE can drive a laptop LCD directly and many other micros would struggle through lack of speed or lack of I/O. It would be nice if it were possible.

 

[Michael 2727]

What ^ ^ ^ ^ Hippy said.
Until recently most G-LCDs even some very tiny ones used Fluoro tubes for illumination,
they need a high voltage inverter (300V to 600V) to fire the tubes.
Usually the thick pink and white wires on a 2 pin plug/s.
Be Careful when playing with these as the high voltage will ZAP and destroy any other circutry it accidently comes into contact with.

Fingers make good conductors, as I once found out trying to retrieve a jammed SD card
from inside my camera. The high voltage capacitor for the Flash was charged and
then discharged through my finger and thumb which fried half of the function buttons.
I barely felt a tingle when it happened, but now only have half a functioning camera.
(lucky it was only a cheapie)

ASUS have seen the Light and are using LED illumination on all of their Eee PC models.

 

[George Sephton]

I think with the small budget i have and the 300V element of it that means no. Although looking at it GLCDs sound quite interesting. Is there a chip for GLCDs equivelant to the Hitachi one for LCDs and a tutorial anywhere explaining GLCDs and how to interface with PICAXE.

 

[manuka]

Perhaps wet your GLCD feet with µOLCDs from Australian 4D systems. These use only PICAXE level voltages (~5V) & are pretty easy to drive. See => http://www.4dsystems.com.au/

 

[westaust55]

gLCD's

Also have a look at some mentioned in this thread
http://www.picaxeforum.co.uk/showthread.php?t=11195

Others have done some work already with gLCD's.
Suggest that you do a search on gLCD and other related terms.

I have played around with small gLCD's out of mobile phones and even with only 102 x 64 pixels, it takes around 2 seconds to refresh the screen at 8MHz.
EVEN These smaller screens (such as I and eclectic have used) have serial data comms so only need a few PICAXE pins, but higher resolution mobile screens and laptop displays are typically parallel data transfer and even some mobile screens use 14 or 16 bit wide data so PICAXE will not have enough IO.

Have a read of this thread I ran when working with a mobile phone gLCD.
look at size of code to have routines to draw text, lines and circles, etc.
http://www.picaxeforum.co.uk/showthread.php?t=10014

Nothing is impossible but few, if any, here have tried interfacing to a laptop LCD screen.

 

[Dippy]

Westy has given a example here of the problems driving GLCDs.
His code takes a couple seconds just to update a few hundred pixels.
A flat-out PIC could probably do the same 10 to 20 times faster, but even so, imagine the speed (or lack of it) for thousands of pixels.
Even for small/medium sized colour GLCDs the PIC struggles (as there are more control lines)and then there are memory issues.

George, unless you can find a driver chip, then put your Dad's notebook back together again!! Driving GLCDs can be a real bitch and very time consuming, believe me. And, sadly, it involves reading Manuf's Data Sheets and understanding timing diagrams.

Summary: Direct drivng of big GLCD with PICAXE: forget it. If Stan can't get it onto a breadboard then you have no chance.

PS. Stan , can we have some nice new (tidied-up) images of breadboards for 2009 please?
With nicer fonts for the labelling. Some of those other ones look like my Dad's 1970s Dymo.
Happy Christmas!