Hello all!
I am working with an LCD for the first time. I am using this LCD: http://www.lcd-module.de/eng/pdf/doma/dips082e.pdf
I wanted to ask before I move forward with this if I can connect my 3.3v and ground along with my pin 3 set at the nominal of .75v (.3/1.2v)(I am using a 100k pot) as per the data sheet to set my contrast to roughly the middle setting and then adjust from there. When I first power the LCD up should I see anything by way of on the screen? I do not have the PIC hooked up yet but wanted to know if I could attach power, 3.3v, first. I tried working with a known working sample and did not have ANY display at all but have power to the lcd via measurement of the vdd pin #2.
Just trying to troubleshoot methodically here. Thanks for your insight.

P

 

It depends. If the .75V is the correct contrast setting or less (or maybe more. I forget which way contrast works), then you shouldn't see anything.

I've always had a trim pot on the contrast pin. To calibrate, I would turn the trim pot until I saw black rectangles, then backed off until they just disappeared.

 

LCD has its own microcontroller. When you power LCD, it goes through a boot process. LCD datasheet should have flow chart that shows that boot process. Part of the boot process is the choice of showing cursor or not, blinking the cursor or not. Since you see nothing when you power the lcd, it is likely that the cursor is turned off.

 

It depends. If the .75V is the correct contrast setting or less (or maybe more. I forget which way contrast works), then you shouldn't see anything.

I've always had a trim pot on the contrast pin. To calibrate, I would turn the trim pot until I saw black rectangles, then backed off until they just disappeared.

And I can do this w/ just the power and ground connected plus the trim pot? Thanks for your help.

P

 

And I can do this w/ just the power and ground connected plus the trim pot? Thanks for your help.

P

Correct power and ground should not hurt it. Don't expect to see much when you apply power. If you adjust the contrast setting you ought to be able to see some change in the pixels (but don't be surprised if you don't).

 

The few lcd displays I've worked with have always showed solid rectangles in the top row until whatever it's connected to initializes it. It may be possible that 3.3 volts is not enough to run the display if you're not seeing anything (I have had it happen with one of mine... but I can't say for sure if it would be a problem with yours.)

 

Running the display with just power and contrast applied is fine. That is how every display first turns on until the controller grabs it anyway.

I am not so sure about running this off a 3.3 volt supply. The only mention of 3.3 v is when a -3.3v supply is also used, but I do not see how to connect this.

Running off 5v is not the end of the world. While your display does not mention input levels the ones I have used are completely in spec when they have a 5v power and signals from 3.3 volts. I would expect yours to follow this pattern also.