Dead display?

[rossfree]

Hi all,

Some time back I ran across a link (in this forum) to bench test a LCD character display. Now I'm unable to find the link. Can someone point me in the right direction?

I have a OPTREX 4x20 display that I am trying to use with a 16f877 and PICBASIC PRO. It doesn't flicker, blink, roll over... nuttin! No characters, no black squares. It acts dead.

I have been able to get a 2x16 working just fine.

If I could make this thing give me a couple of black squares I'd be happy right now. That at least would tell me it's doing something and encourage me to play more with code to get things working right! But I don't know if it even works (purchased new).

There was a link some time back that showed how to bench test these displays. Any help would be appreciated.

Thanks all,

Ross

[mister_e]

Once the LCD is turn on and the Contrast PIN (VO) is set to gnd (or VDD i never remind) you'll see those cute black square.

It assume you properly wire your LCD E, RS, DATA, VCC, VDD, R/W lines too ;o]

[DynamoBen]

Supplying 5V, COM, and V0 w/o the pic should give you black squares. (adjust contrast to both extremes to be sure)

If you get nothing chances are high the display is non-functional.

[rossfree]

Thanks for the replys all. It looks road-kill dead. I've ordered another.

Thinking back, I think I traded a graphics display for this one (buddy of mine). I'll have to give him some @#*& when I see him next. :-)

I'll let you know if I get the other working.

Thanks again,

Ross

[rossfree]

Just got in my new display. Works fine. Pulled out those precious hairs for nothing. Thought it was code... but should have known something was up when I didn't get all those "pretty" squares.

Thanks for the help!

Ross

[DynamoBen]

I've been through the same thing before. First thing I do when I get the display is wire it up to see if there are squares. Then at least I know it worked correctly once.