Hi All -

I want to run this LCD at 3.3V but it's unclear to me what I should be doing with the Vee pin. Do I need to supply it a negative voltage or should it be generating a negative voltage that I feed to Vo from a pot?

Any insight on how to hook this up would be appreciated.

 

the Vee (pin 3) controls the contrast of the LCD. u should connect it to the ground via a 5K or 10K pot. the pot will control the voltage at this pin. by varying the resistance of the pot you will be varying the voltage at this pin which will in turn vary the contrast of the LCD.

usually directly connecting the Vee pin to ground will suffice. but the contrast will change with changing temperatures so u should include a controlling mechanism i.e. a pot.

and if u are unlucky like me u might get a LCD that requires negative voltage on the Vee pin. i have one which needs at least -6V to turn on. in that case directly connecting the the Vee pin to ground is of no help. ask the person from whom u are buying an LCD about this. and tell him that u dont want an LCD that needs a negative voltage on the Vee pin.

just found this somewhere else, hope its useful

 

From the datasheet, the negative voltage is generated as an output, or a positive voltage can be applied to change contrast.

I've not worked with that exact display, but with similar ones, I've only used contrast and ignored any outputs from the LCD.

 

Are u sure u got the 3V version

 

Thanks for the feedback guys. I was under the impression that this LCD would run at 5V or 3V and that at 3V you may need Vee for contrast temperature compensation.

My part is actually a LCD-016N002C YYH-ET, rather than the LCD-016M002C that I linked previously. The technical note on its product page shows that this display does not have a negative voltage generator on board and I confirmed that by powering it up and observing that there's nada on that pin (actually I get no signs of life at all (or Vee) at 3 or 5V).

Most of my projects interface with a PC... the few times I've needed an LCD, I've been a weenie and used one serial backpack or another. This time I thought I'd save a few bucks and interface directly, but now I'm starting think that I picked as less than ideal one to start with.