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sorry . henri sent me a new program to try with my crystalfontz and i haven't yet. i have alot of schoolwork and i really need to do that first. i will let you guys know how it works out when i do. other than that i really didn't use resistors when i hooked up my LCD. i think that the reset circuit that is listed in this thread is the proper one that is needed. i haven't tested it yet, but the reset output appears correct to the CFAG12864B series.

"Wrath" the only thing that i can tell you is to not use the resistors because it appears that they are playing with the current making the LCD react rather slow to any commands. hook it up directly like mine and you will get more promising results. if that doesn't work then try plaing around with the paralell port types as this usually brings different results for every setting. right now i am trying to help henri make his software compatable with the crystalfontz LCDs.

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...and the geeks shall inherit the earth (Bob 5:5)

You used this one + the backlight ?
http://www.skippari.net/lcd/crystalfontzCFAG12864B.gif

You could try leaving the backlight (pins 19,20) disconnected to eliminate one possible place for a problem.

How about grounding ? Have you connected a ground wire from the lpt port to the display ground ?

Do you have a multimeter so that you could check the voltages ? Like when you say the white lines are disappearing slowly does any voltage drop at the same time ?

You could try the reset circuit in the other schematic just to be sure the reset is done correctly. http://www.skippari.net/phpBB2/viewtopic.php?p=328#328

No problem, just report the results when you have time.


From what I understood he didn't use the resistors. The resistors shouldn't affect this, in some cases they could help fix the problem. I know one Displaytech KS0108 display that uses the resistors and it works with same timings as mine which doesn't use the resistors.

I also believe that the Crystalfontz displays should work without changes to the code if the wiring is the same. I've used flat ribbon cable with all my displays, don't know if that has any effect on this.

MarkusM's programs should be a good comparison here. If they work and mine doesn't then I should be able to fix that by adjusting the timings. I believe he's programs use more relaxed timings so cabling/signal quality isn't that critical.

yes


already tried so - doesnt do better


connected all wires marked as ground to ground of my PSU (black wire)


voltage between which pins is needed to be checked?

thx for all answers so far!

I made a pic of how the display looks after having been connected - but havent got any web space, nor do i know how to upload stuff
anyone who could do this for me? would send the pic attached to an e-mail to however could.

when the lines disappear they first become very dark for a short time, and they disappear from the right to the left.
So it looks like that: right side - blue, left side - some white lines, where the white lines just disappeared there are some (3-4 i guess) nearly black pixel

Just send them to the address in my profile and I'll upload it to this server.

I once forgot to connect a straight wire from LPT connector ground to LCD ground and it didn't work at all without it. Just garbage. That's why I asked about this. Only place where it connects to the "power" ground is the display GND point. Don't know if this has any difference.


pin 1 (+5v) should be the first one to check

you could check the pin3 (Vo) too

the picture:

pin 1 = 5.09V
pin 3 = 0V - 0.75V - 0.6V (depending on the potentiometer)

Picture below is from the datasheet. Looking at it the LCD supply voltage (Vdd-Vo) should be about 8.5V.

Symbols:
Vdd = +5V
Vss = GND
Vo = negative contrast voltage

Vo (pin3) should be about -3.5V to get the LCD supply voltage to required levels.

So it looks like there is something wrong with your display. How about the Vee (pin18) ? What's the voltage there ?

Checked all of the Voltages
Pin 8 ~0.60V
Pin 12, 13 = 4.92V
pin 14=5.09V
pin 16=2.93-3.07V
pin 19=3.7V

How about pin 18 ? You should get a reading from there too. Negative would be preferred.

Was there any program running when you measured these ?

Err - the LCD wasnt even connected to LTP,... no program running

i got no negative voltage at the display at all
pin18 is about 0 - 0.5V or something like that, depending on the potentiometer,..
seems i have to wire it all over again? or is the LCD messed up? Can i only connect a few wires to it to check if the negative voltage inverter does work?

Sure.

Try removing the potentiometer and then re-measuring the pins 1 and 18.