20x4 lcd not working..

[Ttelmah]

One good guide, is to look at what data the companies offer.

As I already said, I wouldn't buy a display were the data was this poor. Basically doing so, is 'asking for trouble'. With proper data, you would have timing diagrams of what the data should look like on the pins. With a scope of logic analyser, you could then check you were doing what it 'expected'. Similarly there would be specifications for everything like the contrast voltage etc..
You then have a chance of knowing what is wrong.

If you look at displays from another 'Asian' company (Powertip), their basic data sheet for the 20*4 modules, is 1.4MB, versus the 30ish KB of the one for your display. You have everything including examples of timings, character generator contents (and options), timing sequences, etc. etc.. They then have five more sheets giving back-lighting specifications, examples etc.

One reason the display is cheap, is probably zero testing. In one sense you 'get what you pay for'.....

Think what your time is worth, and then what it'll cost for every unit that doesn't work.

Look at somebody like <http://www.digibay.in/display/20x4-character-lcd-module-green-hd44780-controller-jhd-204>

That is a standard module, with reasonable data.

[Krazzy7434]

Hello guys...
i m going to assume that my lcd is damaged...
Thank You all for the help....
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Krazzy7434

[gpsmikey]

Often times for projects like this, it is worth it to buy 2 of whatever you are working with if you don't have access to any others. That way, you can verify the item is functional (if both act the same) or has a problem. When you look at your time, often that is cheaper (and often the shipping is almost the same for 2 as it is for 1).

mikey
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mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3