Where do you find LCD pinouts?

[choppergirl]

Hi, I just salvaged a dotmatrix Sharp LM40A21 2x40 HD44780 LCD unit off an old POS terminal from the early 80's. It seems to be a fairly common unit.

Its got an HD44780 chip on it, it should be a cinch to wire it up to a parrallel cable and build my first LCD smartie, and start writting some code for it to display game server stats.


I can find the datashee to it: http://www.datasheetcatalog.org/datashe ... Xtzzrx.pdf

But what google terms do I punch in to find the pinouts of the 14 wire ribbon cable that connects to it?

TIA
CHOPPERGIRL
http://choppergirl.air-war.org

[choppergirl]

It has 14 pinouts, instead of the 16 or 18 like shown in the wiring diagram on this website
http://lcdsmartie.sourceforge.net/circuits.htm

i assume the red line ribbon cable wire is pin 1, and the pinouts are staggered, so going down the ribbon cable, the wire next to the red line ribbon cable woudl be pin 2, and so on down the ribbon cable.

It has no backlight, so I'm guessing the missing pins (14 instead of 16/18) are for the lack of a back light.

[mattcro]

There doesn't seem to be much info for displays like this, but you can try wiring yours up according to the first 14 pins on the top diagram on the Smartie wiring page, with the red wire as pin 1. Pins 15/16 on the top diagram are only for the backlight power.

[choppergirl]

Well, I thought the same thing, just wire it up using the first 14 pins. Looking at the datasheet, it says where pins 1/2 and 13/14 are on the physical diagram.

So its all wired up with +5v to pin 2, and ground to pin 1, and all the data lines, and lines 3-5 to whatever (R/s,RW, and E). The only thing I did different was I don't have a 10k pot to adjust the contrast, so I wired pine 3 (VLc) straight to ground instead of with an in-line potentiometer.

I can't get it to do anything at all.

I went into bios and made sure printer port was enabled (ECP) - do I need to use EPP?

I installed the NT printer port driver as directed.

I then setup LCD smartie to use HD44780.dll on LPT1, and set screen to 2x40

Anything else I can do???

[choppergirl]

I also tried wiring the contrast line to +5v, or leave it open, or ground it, no difference.

I set my printer port to EPP in bios on 378
http://lcdsmartie.sourceforge.net/HDSetup.html

I tried adding the boot delay of 5 ie LPT1,5

I also read this page under... "Why doesn't my HD44780 controlled LCD work?"
http://lcdsmartie.sourceforge.net/FAQ.htm


I can only guess, the pinouts are different that this wiring diagram, or the display is dead...

[choppergirl]

Ok, I'm looking at an ebay listing for some other HD44780 display, and this one has a shifted pinout:



http://cgi.ebay.com/16x2-HD44780-Charac ... 33559a0927


Maybe if I try this pinout..

GRRR!!!

[choppergirl]

OH SNAP, I GOT SOMETHING



I started wiring it up like that diagram above with all the pins shifted one, with the ground at 14, and +5 at pin 1 and 2, and shifted the data initiate pinsand I'm getting some block characters on the screen. So I know it works. I just got to shift all these 8 data pins

[choppergirl]

Still no luck. Here is one I found for sale on ebay. I asked the guy for a pinout but I double he'll give it to me as he probably doesn't have it himself...

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... Track=true

[choppergirl]

Grr, even this is wrong, according to my multimeter, GND is on pin 2 (or pin 13, if you put the ribbon cable the wrong way around) either way, its a non-standard pinout.

I found the pinouts for an HD4478A00 chip, I thought I could trace using the multimeter from its pinouts to the pinouts on the main motherboard and figure them out that way...

http://mechatronics.me.wisc.edu/labreso ... CD-II).pdf
(page 4 is how my chip looks like)

But no, testing from the chip to pinouts only helps in identifying ground, nothing else. I get a buzz on my ttl probe on too many pins and can't narrow down at all which goes to what...

I wrote to Sharp, maybe they will help. This is bullshit.

If I had soldering skills of the gods, I could solder tiny hair like wires coming right off the HD4478 chip to a breakout box, and wire directly to that, but the leads to the chip are so impossibly small I could never do that.

By using a multimeter set to diode test to follow traces back to the pins from the chip pinouts, this is what I get (!)

pin
1 VCC
2 GND (VSS)
3 RS
4 V5 (VLc)
5 E
6 RW
7 D1
8 D0
9 D3
10 D2
11 D5
12 D4
13 D7
14 D6

Good lord, compare that to http://lcdsmartie.sourceforge.net/circuits.htm



I see what they did, they solder the pinout coming out the back of the display until, instead on the front, which screwed up and mixed up all the wires coming off the ribbon cable. If you look at it from the front of the display, on the side on which the pinout header should of be soldered, its all normal standard layout... fucking idiots...
http://www.epemag.com/lcd1.pdf

http://www.epemag.com/lcd2.pdf

I'm getting some block characters out now that change and flicker when Smartie changes, and every now and then i see a character or two, so its doing something... finally

[caesar]

Quite a job you did on new years eave!

If you followed the traces with the multimeter then it can't be wrong.
Black blocks on the first line are supposed to appear at powerup, it's a good sign.

PS: If you use 64bit XP or any versions of Vista/Win 7 then you must use inpout32 instead of port95nt