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Author Topic: auto contrast display.  (Read 415 times)
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uk
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hi,
ive just brought a 20 4 display just noticed thats its an auto contrast display, i cant get it to go, its set us as "hello world" just wondering if i should feed +5v into V0 as thats where the wiper went?
thank you

ive just noticed a very very very  faint, hello world, how can wind it up if its auto contrast??
« Last Edit: June 07, 2012, 12:50:30 pm by jonisonvespa » Logged

Maaseik, Belgium
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What do you mean with an "auto-contrast"?

You always have to adjust the contrast with a potentiometer. You find it in the datasheet of your lcd.
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uk
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it says on the back,
please note, the contrast in this display is automatic and so pin 3 need not be connected. if an adjustment trimmer is provided it will have no effect
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Western New York, USA
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Quote
...just wondering if i should feed +5v into V0 as thats where the wiper went?
Typically there is about 1/2 volt on pin 3 when the contrast is set correctly so +5V would not be a good choice.

Quote
it says on the back,
please note, the contrast in this display is automatic and so pin 3 need not be connected. if an adjustment trimmer is provided it will have no effect
There should be some sort of photosensitive device on the board to activate the 'automatic' function.

You are asking us to diagnose an unknown device and you are feeding us the clues one by one.  Why don't you just give us all the information that you have.  A photograph of each side of the board would be helpful.

Don
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uk
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thanks for the help, i didnt have pins 15,16 connected. all ok now
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