Need Help wiring an character LCD

**veetid** · 12-14-2004, 11:40 PM

I am trying to add support for LCD's in my application. I acquired this LCD from the front of an old server at work. I searched google and think I found the specs.

http://www.fluxmedia.net/downloads/dv20200.pdf

The specs talk about it having 16 pins, but when it was connected on the server there was only a 14 pin connector that plugged into the pins on the left hand side of the front picture. The other two pins mentioned are A and K, which you can see on the left hand side of the back picture, but nothing was hooked up there and they aren't pins. I am no good with hardware modding. I need to interface it with serial or parallel, not sure which one, in order to use it. I know nothing about this stuff, so I need someone to help me make a cable to be able to use this on my computer. I can send the LCD it to anyone if need be.

Is this the kind of LCD other people use? This should be possible and work right?

http://www.fluxmedia.net/downloads/lcdback.jpg
http://www.fluxmedia.net/downloads/lcdfront.jpg

david

**Aksor** · 12-15-2004, 03:01 PM

The 14 pins are the actual Data and power to the interface and the A and K stand for Anode(+) and Kathode(-) of the LED backlihgt.

do a search for the Winamp LCD plugin and it will give you a wiring diagram on how to connect your unit to the printer port

**veetid** · 12-15-2004, 04:48 PM

Thanks for the info... I found a bunch of information, but there was so many different ways to wire it. Which one should I choose? I want to set this up in the same way as other people in the forum, so when I write the code to communicate with it, it will be compatible. Also... What is all the talk about how many keypads it supports? I admit I know nothing about this stuff and sorry if these are basic questions...

Is this the one I should follow:

http://www.markuszehnder.ch/projects...allel_8bit.gif

I am also not sure about whether mine is an 8 bit display, like it mentions..

If that is the picture to follow, then everything looks fine except There are some that are labeled different. My top three are Vss, Vdd, Vee. The ones in the image are Vss, Vcc, VLc. Does this matter? I also don't understand what is going on with the pins 18-25 on the printer port.... It has all those linked to the ground and power. It also looks like they wired VLc someway into the same as the Vcc (5v). This one is labeled Vee for LCD Drive on mine. How does that work.

I understand wiring the RS, RW, E, DB0-DB7. I assume I do nothing with the VB+ & VB-, they represent my A & K. Then just run my Vss (ground) to some ground port on the printer connector (which is it) and supply 5V to the one wire Vdd (why was this wired into the printer connector in the photo). Also not sure what to do with the lcd drive Vee.

thanks

**veetid** · 12-16-2004, 10:51 AM

*bump*

**rando** · 12-16-2004, 02:46 PM

I've never used one but I believe

Vss - GND
Vdd - Power supply
Vee - Contrast adjust

You set the contrast by adjusting the Vee voltage between Vss and Vdd.

**nzKAOSnz** · 12-16-2004, 04:56 PM

Be very careful with the contrast adjust. I.e research it WELL before putting power to it. I have a lcd that the contrast is between 0 and -5v. So 5v made one LCD go puff.

**veetid** · 12-16-2004, 05:25 PM

Do I even need to hook up power to the contrast one? Can I not just wire all the data leads and the the ground to the parallel port. Then just give 5V to the one 5V lead? In the wiring diagram in the 3 post it shows the other power drive somehow already connected to the original 5V.

david

**Aksor** · 12-17-2004, 11:21 AM

Like rando mentioned above

Vdd = Vcc = +5V
Vss = Gnd = 0V
Vee = VLc = depends on the LCD but most will work between 0-5v

As for pins 18-25 they are the ground on the printer port.

You will need to steal power from one of the drive connectors as the Printer port does not supply any, the red wire on the HD connector is +5V and any of the Black ones is the Gnd.

As for Vee just connect it to ground. If you want to adjust the contrast then connect a 10-20K potentiometer between +5V and Gnd then take the wiper of the pot and connect it to the Vee terminal.

I hope this helps and good luck

**veetid** · 12-19-2004, 06:52 PM

I appreciate everyones help... I wired it all up today and it works great... Here is a pic of it running and another of the cable I made... I connected a DC plug for the 5V power source. Now I can get power from multiple places. I have a bunch of cables with dc plugs. I have one for the keyboard port, a usb one, and a molex one...