HELP with LCD Display, All I'm getting is JIBBERISH :(

[Araltd]

I have a 2x20 lcd display, that I bought from bgmicro.com, with a 4-bit hd44780 interface, its actually an equiv. controller, the chips on the back are: two OKI M5839B - 7252B02 (2 small square chips) and 1 large SANYO LC7985NA - 8733 7F3

I've got it hooked up, using the attached schematic. I'm running WinXP-SP1, I've installed the Port95nt, and tried using several lcd proggies. No luck. The one that actually makes the jibberish is smartie-lcd 5.1

Can you help?
[email protected]

 

[Araltd]

Its connected to the parallel port, btw. And I've tried SPP, EPP and ECP. Same results...

 

[Sniperboy]

You might want to check all your soldering and make sure that it's all wired correctly and you haven't accidently connected two wires with solder. Hope this helps!

 

[Araltd]

All my connections are solid, and nothing is bridged.

I wish this damn thing worked

 

[nixie]

have you got the option of using the 8 bit interface?

 

[Crazy Jayhawk]

Make sure you didn't accidentally "flip" the wires when you were doing the connections to the 25-pin plug. I've accidentally wired some DB-9 connectors backwards and it took me a while to figure out what the problem was.

 

[Araltd]

have you got the option of using the 8 bit interface?

Not that I'm aware of. From what I've read, the "E" line tells the interface (parallel port) to send either the HIGH data or LOW data, alternating between the two 4-bit paths, essentially giving you 8-bits of data.

At this point, I'm gonna have to guess its a software issue, meaning smartie-lcd and alike are not giving the parallel port the needed 4-bit data, and only supplying data to the port in an 8-bit configuration - but of course, I'm an idiot, and really don't know what I'm talking about so it makes figuring this out even harder

Make sure you didn't accidentally "flip" the wires when you were doing the connections to the 25-pin plug. I've accidentally wired some DB-9 connectors backwards and it took me a while to figure out what the problem was.

No- the connections are correct, the DB25 I used was labelled, and I've done DB stuff before... I'm positive the wires are connected, not bridged and connected to the right DB leads.. What I'm not 100% sure about is if I used the correct pin-to-pin configuration. I think I'm gonna give up on these LCD's. I only wanted to use them because they were $5/ea with backlights. Can't beat that- but I'm 99% sure they will require A) special software to talk to them, as most LCD's from what I've read, are 8-bit interface, and these are 4-bit, or B) a Serial backport, allowing connection to the serial port, which is about $15-$20. I can buy a "correct" 8-bit LCD for that from eio.com

Thanks for the help guys.