Graphic LCD power

beny1949

Senior Member
I have got a few 122x36 pixel LCD's from ebay, and i have been trying to work out what i need to do with the Vlcd pin which is the power fot the LCD.

I do not know if there is a way of telling if there is a built in inverter (charge pump) or if it needs to be supplied with -5 volts?

here is a link to a copy of the data sheet: http://ben-howes.co.uk/GraphicLCD.pdf

So, if anyone knows what should be done with this please let me know!

Ben
 

hippy

Senior Member
It's not very clear is it !

My reading of it ( Section 10 - Pin Connections ) is that it's a voltage which sets the contrast as per other LCD's as there's no other pin to do that, and ( Section 3) it can be a signal -5V to +5V; 'Vdd-Vlcd = 0V min, 10V max", when Vdd = 5V.

If Section 6.1 had been filled in it would have been a help ;-)

You could try emailing Falcon or search Google for any other info you can find on the module.
 

BeanieBots

Moderator
Not obvious is it.:confused:
It says "supply voltage for LCD = Vdd-Vlcd = 10.0v max"

As Vdd=5v (typ), for that equation to be true, it would suggest that Vlcd should be between 0v and -5v.
Maybe google will show something a bit more helpful?
 

beny1949

Senior Member
I have had a look on google, but i cannot seem to find anything about 'falcon' who make LCD displays. There are other Falcon electronics ect. who mostly seem to specialise in millitary electronics.

i have emailed the person who i bought it from, so hopefully i will hear from him soon.

If we can collectively get the screens going ok, it would be very handy, because they are just £2.50 for two from ebay! what a bargin. They make up for poor data sheets with rock bottom prices it would seem....
 

BeanieBots

Moderator
They make up for poor data sheets with rock bottom prices it would seem.....
Either that or they use an obscure control that nobody can get to work:eek:
If they can be made to work, then a very good price indeed:)
A -5v supply is always a pain to create but can be done with a PICAXE PWMout line and a few caps+diode so not the end of the world.
 

beny1949

Senior Member
it would appear that the LCD does need a -5 volt Supply!

onto the next barrier.... will post in a new thread to save confusion
 
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