LCD display help

I picked up an LCD display this weekend. It was a great deal at $2. Now I just need to figure out how to use it.

The unit has 12 HD61100A and 2 HD61103A chips on the back. So I’m pretty sure it’s around 960x128, but I could be way off.

I’ve narrowed down the wiring to 4 power leads and 8 data lines. The power leads are guessable, based on the data sheet info:
White Vcc (+5V)
Black Gnd
Brown Vee (-V:0 to -11.5 accroding to data sheets)
Red looks like some sort of enable line at a -V level. It’s wired directly to the base of a PNP (A673AKC) transistor

The 8 data lines are where I’m at a loss. They are buffered by a bus tranceiver (74LS245), which also has pull-up resistors on all 8 lines in both directions (on the little extra PCB in the pic). I suspect data has to be fed in sets of some sort that probably are based on the screen res? I figure there’s also some control bits. I also can assume there is some sort of feedback that I have to consume. That’s all I’ve got so far.

If anyone has any ideas/suggestions/general concepts about this thing, let me know (even if you just know of another site that can help). At 2 bux, I’m not real worried about blowing it up. But it would be much cooler not to. :wink:


Full res image:

What?!? No one wants to jump in on this? He he. :smiley:

I was able to get it to display some intentional garbage. I’m still learning how LCDs are even addressed at this resolution, but I did figure out the functions of all the wires by probing them with a continuity tester and comparing to the data sheets for the two main chip types.

In case anyone’s interested, the screen is 480 x 128. It’s divided into 4 quadrants (240 x 64), each driven by 3 HD61100A chips, two quads share one HD61103A chip. The 8 wires are 5 serial data lines (one for the columns in each quad and one for all rows) and 3 common clock lines. The 4 power leads are +5V, Gnd, -9V (works, but could be -12V) and Contrast ref’d to the -V. It’s NOT a bi-directional interface as I had originally thought (whew!)

I’ll update with the actual pinouts when I get home from work tonight.

So far it looks like this thing has way too many dots for the Arduino to address in a timely manner. So I’m just farting around with one quadrant for now. Maybe when I wrap my head around the addressing a bit better, I can speed it up to a usable rate.

I’m also thinking some shift registers will help speed it up a bit, since I have to address all 8 pins at once anyway, I can just turn that into a bit map and shift them in… maybe. Not sure that will help much.

Geeking out over here… Cheers!

GAAA!! Fried it! Damn. Touched one of the data lines to the -Vin and poof!

Almost had it figured out too. It’s missing a third chip - an LCD driver that is pretty common I guess. But I can still drive it myself. I just needed to dial in the timing between the horizontal and vertical data streams. I may be able to use the LCD serial back pack from Sparkfun to drive it (big maybe).

I’ll have to see if they can ship me a couple more.