Problem identifying an LCD

Other Hardware Displays
1

Hi,
I just salvaged an LDC from a credit card terminal and I'm having problems with getting it to work. It's a graphic display and I think the resolution is 128x64, I haven't counted the pixels... :slight_smile:

I don't have the datasheet for it but on the backside it says EDT EW50294GLY 0412A*22. After some googling I found Emerging Display Technologies, and although the EW50294GLY isn't listed there it seems like the naming is similar.
http://www.edtc.com/edt/Products/graphic.asp?search=graphic

So left without a datasheet I took a shot and assumed it's a KS0108-type. I tried both the current and beta versions of GLCD using the "A"-type. Pin 1 on the board has a red cable an I figured that to be 5V and hence type "A". The display lights up and when I turn the 10k contrast pot to max almost all pixels go black.

I have tried to run some example code from GLCD including the the GLCDdiags sketch from the beta. Here's the output from that:

Serial initialized

GLCD Lib Configuration: glcd ver: 3 glcd_Device ver: 1 gText ver: 1
Panel Configuration:ks0108
Pin Configuration:ks0108-Arduino

GLCD:ks0108 DisplayWidth:128 DisplayHeight:64
Chips:2 ChipWidth:64 ChipHeight:64
CSEL1:14(PIN_C0) CSEL2:15(PIN_C1)
RW:16(PIN_C2) DI:17(PIN_C3) EN:18(PIN_C4)
D0:8(PIN_B0) D1:9(PIN_B1) D2:10(PIN_B2) D3:11(PIN_B3)
D4:4(PIN_D4) D5:5(PIN_D5) D6:6(PIN_D6) D7:7(PIN_D7)
Delays: tDDR:320 tAS:140 tDSW:200 tWH:450 tWL:450
ChipSelects: CHIP0:(14,0x1, 15,0x0) CHIP1:(14,0x0, 15,0x1)
Data mode:
d0-d3:nibble mode-Non-Atomic
d4-d7:nibble mode-Non-Atomic

Diag Loop: 1
Initializing GLCD

I guess the initialization doesn't really work. So, maybe it's not a KS0108?

Any thoughts?

/Jörgen

2

Forgot to mention that I have an Arduino Uno.

/Jörgen

3

It still might be a ks0108.
Unfortunately with ks0108 lcds, you pretty much have to have all the pins
hooked up correctly to be able see anything happen.

In working with ks0108 displays (while I was updating the glcd v3 library low level
code and writing the glcd diag sketch), I saw more than 10 different pinouts
for ks0108 glcd modules.
There are many more than just A, B, & C shown on the playground page.
For 128x64 displays, those are the most common.

What you are seeing in that message from the diag sketch is that the low
level glcd initialization code is failing. It is hung in a loop "waiting" for the
BUSY status to go away.

This can occur for many reasons, but is almost always due to incorrect wiring.
In order for the BUSY status to work properly,
EN, RW, CSEL1, CSEL2, DI, RESET, and Databit7 have to be hooked up properly.

When I re-release the library soon to add in mega2560 support, I'll add a few more
messages to the diags to catch this "stuck BUSY" issue and report it
rather than silently hang inside the initialization code.

But I would definitely stick with the glcd v3 library as it is much more
robust and feature rich than the previous ks0108 library.

====

Some additional questions:

Was this display working in the device it was removed from?
and did you see things on it that were definitely graphics so
you know it wasn't say a 20x4 line display?

====

The tricky and most important part on ks0108 displays is to get the power connections
correct. Get those wrong and you can burn up the part.
The "type A" pinout isn't that common.

But the good news is, pins 1, 2, 3, 18, 19, & 20 are almost always all power related.
Most ks0108s use those pins for power and usually the only pinout differences
are 1&2 swap around and 19 & 20 swap around.
Since you are seeing the backlight come on and you see pixels turn on when you
adjust the contrast pin, it looks like you got all the power lines correct.

Different manufactures have different ordering for their pinouts:
For example: most use pin ordering like:

lcd power, data lines, chip selects, reset, control lines, contrast power, backlight power
lcd power, control lines, data lines, chip selects, reset, contrast power, backlight power.

Most I've seen tend to put the control lines right after lcd power, or the lower
of the two examples above.

My suggestion at this point is to re-wire it with a more common control and
data line configuration.
(There are other possibilities, but this is fairly common and should be easy to re-wire)

So leave the connections to pins 1,2,3,18,19 & 20 alone and
swap around the other pins as noted in either "B" or "C".
The only difference between B & C is the left & right halves of the display are swapped
and it won't matter to get the display up and working enough to see something.

--- bill

4

It's working now!
I was fooled by the cable on pin1 being red. I assumed that was the +5V but it probably was red just to show that it was pin1.

I tried the "Panel B" pin configuration and after making sure I had all the cables hooked up correctly it works.

Thanks for the help Bill!

/Jörgen