kristianlein@hotmail.com

Hi everyone!
This is my first post! Hope it's not a hard one ...

I've been having a lot of trouble with my 16x1 character lcd module:
GTC16011 TR6N0C (bough from http://www.elfa.se/elfa-bin/dyndok.p...o&dok=6468.htm if thats of any interest). It just doesn't show anything.

I have read that you are supposed to get half of the lcd display to be blacked out while the other half is supposed to be white. Should this occur once you give the lcd power supply?

Also, when I hook the enable pin (pin 6) up to a 5V supply, the device gets hot ... i though this enable pin was supposed to be high-impedance mode and not much current thru? Is it broken, perhaps?

Appreciate all help! Thanks!
Kris

ClydeCrashKop

If it has the typical HD44780 controller, it might be just the contrast adjustment. Mine has to be almost at ground to display. Check the circuits in Nigel’s tutorials.

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kristianlein@hotmail.com

Hey ClydeCrashKop!

Yes, its a normal HD44780 controller or a compatible one.

I don't think its a contrast problem - when I tough the back side of the lcd module, i see strange patterns on the display (which slowly fade away as I remove my finger). The contrast adjust is already grounded ...

I'm out of ideas of what could be wrong ...

It would help to know what is necessary to get the display to show the test-pattern.

blueroomelectronics

You don't ground the contrast, you generally need a trimpot. If it's getting hot it's probably not working or was wired wrong. NEVER reverse pins 1&2 on an LCD display, will almost always kill it.

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kristianlein@hotmail.com

thanks for the nice pin diagram ... it looks a lot like mine so thats good (or is it?)

although i don't understand what i've done wrong, I think the lcd may be broken. it can't be normal to have it such current out of an input pin such as 'enable', can it?

i might give up for now, until i get a new lcd.
but thanks!

blueroomelectronics

Enable should not affect the current consumption. A typical LCD panel like that draws very little current, the backlight if you have one draws the big juice.
There's an LCD tutorial site in the links section of my homepage.

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kristianlein@hotmail.com

yes thats what i though!
when i connect 5v to the enable pin, not only does it draw a significant amount of current, but it makes the whole things go really hot.

i've got earth on pin 1 and 5v on Vlogic, then with 5v on the enable pin, it goes hot - can I safely conclude it's broken?

Nigel Goodwin

I would suggest if it is broken, then you probably broke it connecting it wrongly? - it's really very rare for one to fail.

But as suggested, if you're grounding the contrast pin it won't work anyway (or at least you won't see anything).

Simple test - apply power and ground to the module, and a contrast pot between power and ground, feeding the contrast pin from the slider - nothing else connected.

If the module is working, then by adjusting the contrast you should be able to get a row of solid black squares.

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kristianlein@hotmail.com

ok perfect, i was looking for such a test. and all lcd's have this "test-screen"?

if that's the case, mine is broken. i must have "misconnected" it, cause all I'm getting with your test is strange patterns on the screen when i touch the backside of the lcd.... fair enough.

(argh! all that debugging for no use!)

Thanks a lot Nigel & blueroomelectronics

Cry_Wolf

well when i worked on lcds they worked fine when u give them groun on Vd(contrast pin). try giving Vdd(5v), GND and a ground on Vd(contrast), and leave other pins floating (donot connect them). If the LCD is not broken it will show up black boxes ...

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