LCD Wiring help

A

atom

Gawd
Joined
May 3, 2005
Messages
858
Ok I want to start off saying this is my first lcd project so I am just figuring out how this works. I ordered a 4bit LCD off of bg micro and couldnt wait to recieve it and wire it to my computer via the parallel port. Little did I realize that I needed an lcd with 8BIT wiring not 4BIT! Woops. Ok so I found a pdf for my lcd's 44780 clone the LC9785NA. The 4bit pinout is assumed to be the same standard and I traced the 4 data lines to DB4 DB5 DB6 DB7 so I assume when using 4bit wiring you use the upper 4 bits? So do i just simply wire the lower 4bits as my first 4 data lines or do I wire them as my last 4 data lines after the other 4? Does what im saying make sense? Lol sorry. Another question I have is about this baby el blue lighting. El lighting runs off AC electricity correct? Any idea what sort of voltage I should send it?
 
What you said about the LCD made no sense to me, but..

About the EL wiring...why don't you just use the inverter it comes with? Or did you just find some laying around?
 
Its an el blob behind the actual lcd screen not el wire and came with no inverter. But I got this all figured out by doing some more reseach (rtfm) and I will hopefully get this working tommorow and will post some pics.
 
atom said:
Ok I want to start off saying this is my first lcd project so I am just figuring out how this works. I ordered a 4bit LCD off of bg micro and couldnt wait to recieve it and wire it to my computer via the parallel port. Little did I realize that I needed an lcd with 8BIT wiring not 4BIT! Woops. Ok so I found a pdf for my lcd's 44780 clone the LC9785NA. The 4bit pinout is assumed to be the same standard and I traced the 4 data lines to DB4 DB5 DB6 DB7 so I assume when using 4bit wiring you use the upper 4 bits? So do i just simply wire the lower 4bits as my first 4 data lines or do I wire them as my last 4 data lines after the other 4? Does what im saying make sense? Lol sorry. Another question I have is about this baby el blue lighting. El lighting runs off AC electricity correct? Any idea what sort of voltage I should send it?
Click to expand...

I'm not following what you're saying.. but as far as i know.. ALL hitachi interface LCDs are 8-bit at start up. you have to send commands to make it 4-bits.
 
RancidWAnnaRIot said:
I'm not following what you're saying.. but as far as i know.. ALL hitachi interface LCDs are 8-bit at start up. you have to send commands to make it 4-bits.
Click to expand...

Nope, it has 10 pins on the pcb and only 4 of them are data lines. 4Bit Parallel. I am tapping the other data lines directly from the IC to make it 8 bit.Its not a hitachi IC its a clone with different pinout. The question was in what order to send the bits but I have figured that out now. I wasnt asking what the IC supported but wondering how to wire the IC since the board was wired to the IC in a 4 bit setup. Do I make sense now? Its kinda hard to explain without pretty much coming out and saying nothing but techincal terms. But like I said ill take pictures soon.
 
atom said:
Nope, it has 10 pins on the pcb and only 4 of them are data lines. 4Bit Parallel. I am tapping the other data lines directly from the IC to make it 8 bit.Its not a hitachi IC its a clone with different pinout. The question was in what order to send the bits but I have figured that out now. I wasnt asking what the IC supported but wondering how to wire the IC since the board was wired to the IC in a 4 bit setup. Do I make sense now? Its kinda hard to explain without pretty much coming out and saying nothing but techincal terms. But like I said ill take pictures soon.
Click to expand...


i would just like to see a data sheet.. cause i'm still not following you..
 
Frank4d said:
Is this datasheet correct for your LCD? >> http://www.bgmicro.com/pdf/2x16el.pdf
Click to expand...


If tha is his LCD.. then it is was i said earlier.. you can operate in 8 bit mode.. or 4 bit.. jsut like any LCD... so i still don't understand what hte OP is asking.. Also..

it appears that in 4 bit mode you send the most significant nibble first..

OKay after reading your posts again.. i think i see..

so you're saying.. that the Controller on the LCD does support 8 bit mode.. BUT!! that the way the manufacture did it.. is they only pulled out 4 of the data lines on that actually controller?? and now you're trying to tap the other 8???

Also.. why do you need to do that??

can't you run it in 4 bit mode?? why do you need 8??

how are you programming this module?? if the parallel line on your computer is 8 bits.. that's fine.. use 4 for data, and then the other 4 for En, RS, anf RW, though you can tie RW to ground so that it's always in write mode.. most peopel don't need to read from an LCD..

what i just said requiers only 6 bits or 7 bits.. and you can do it since you for 8 parallel bits.. you're just gonna gonna use the last bit of the 8... is this what you're asking??

you don't need to tap the other 4 bits... this is hte purpose of having a 4 bit mode LCD.. so that you can run the wholething off of less pins
 
so you're saying.. that the Controller on the LCD does support 8 bit mode.. BUT!! that the way the manufacture did it.. is they only pulled out 4 of the data lines on that actually controller?? and now you're trying to tap the other 8???
Click to expand...

Yes! I just want to use LCD smartie or a similiar program. The ones I see all require the 8bit wiring. Im not doing any programming here. I asked a really dumb question on which nibble goes first (as in what pin order corresponding to the pc) and after a little bit of googling i figured it all out. I now see how I confused you guys as I made it seem like a coding question. No guys thats not the lcd im using and there is no specsheet for it I could find.

:p Sorry im a doufus
 
atom said:
Yes! I just want to use LCD smartie or a similiar program. The ones I see all require the 8bit wiring. Im not doing any programming here. I asked a really dumb question on which nibble goes first (as in what pin order corresponding to the pc) and after a little bit of googling i figured it all out. I now see how I confused you guys as I made it seem like a coding question. No guys thats not the lcd im using and there is no specsheet for it I could find.

:p Sorry im a doufus
Click to expand...


OOOhh okay lol...

interesting.. i don't tink i can help you much there.. I always program my LCDs.. and i always use 4 bit mode (to save pins on micro controllers).. i've never interfaced an LCD to a PC... sounds like a fun project though

so the controller that's on the board.. do you know the physical location of the pins that represent the 4 bits you're looking for??

maybe you cna look up a data sheet on the controller itself and not the LCD??

depending on the type of package the controller comes in.. it could be a bitch to tap the pins, you could short someting out and cause magic smoke to release..
 
Yeah i found a pdf for the IC and the pins I need were exactly where I figured they were. Yes, they are really small pins and it will be a bitch to do! I do have some bad experience with this doing console mods but I think if i take my time I can do it. I am going to attempt to backlight this baby with some red leds so it will match my color scheme. Good luck to me here I go!
 
atom said:
Yeah i found a pdf for the IC and the pins I need were exactly where I figured they were. Yes, they are really small pins and it will be a bitch to do! I do have some bad experience with this doing console mods but I think if i take my time I can do it. I am going to attempt to backlight this baby with some red leds so it will match my color scheme. Good luck to me here I go!
Click to expand...

Good luck LOL..


if you figured all this out why did you even post the thread LOL!!!

good luck man..
 
I am working on wiring up this lcd screen to the front of my computer to show instant messages, game stats, mp3s the weather, newsfeeds all sorts of neat stuff.

1.JPG

Just to show you my awful work area. Girlfriends dog crapped on the floor right there too.


4.JPG

This is what im working with here. Problem is the software that sends text to the lcd requires an 8bit interface. This lcd has a 4bit interface. This is where the fun part happens.

2.JPG

I need to tap wires into the highlighted pins here to send the other half of the signal. I found this out by tracing the little lines and looking at the pdf i mentioned earlier.

5.JPG

just to show you hall small it is and what im working with

6.JPG

this is the best non blurry picture i could get of this part. You cant even see it but I have succesfully detached the pins from the circuit board and they are still connected to the chip and floating in the air. I did this because 2 of these non used pins had traces going to them which i believe led to ground.

What I need to do next:
Tap wires to those pins and interface to the parallel port connector. I havent done this yet because my soldering skills are terrible and I need to get something special to do this. I also need to interface the rest of this lcd yet and get some red leds to backlight it. I already bought some but i burnt them out with the soldering iron (didnt i say i suck at soldering?) This is taking a lot longer then I want and im pretty frustrated. First I order the wrong lcd, then I realize I didnt buy all the little parts I need. I got to radio shack and spend 15 bucks on a potentiometer, a knob, 2 leds and a 15pin connector. 15 bucks! That means ive speant 20 bucks on this project when a retail one would be 40 and the retail one would be usb and a lot prettier! Oh well.
 
huummmm you know... if you're gonna put this thing on your computer...

i would have told you to just forget this LCd and get a really nice like color one.. you know.. with a black background and blue letters( or green, or white.. etc..)

a nice optrex

something like this

Now that is pretty... i used that one on a robot i built.. lol...

but if you decided to stick with what you're doing.. GL lol.. i don't know what else to say
 
Yeah ofcourse a lot of fun an experiment like that. Alternatively you can pickup a true HD44780 display on ebay for a couple of bucks.

edit: i forgot to mention LCDinfo supports 4-bit HD44780 ;)
 
Im in between jobs now so im working with what i accidently ordered with the last of my money.
 
You must log in or register to reply here.
Back
Top