GxEPD2 - How to know which Display to select?

Other Hardware Displays
1

Hello

I got a 1.54" Waveshare display today (well, yesterday, by now) and have spent all day and night trying to get it to work properly.

It took me a mighty long time to realize which display to select.
I can't find any information stating exactly which display I got, and the datasheet doesn't seem to give any information on the variations or even what differs between them.

Trial and error finally got me to realize I have the DEPG0150BN

DEPG0150BN 200x200, SSD1681, (FPC8101), TTGO T5 V2.4.1
GDEP015OC1 200x200, IL3829, (WFC0000CZ07), no longer available
GDEH0154D67 200x200, SSD1681, (HINK-E154A07-A1)
GDEW0154M09 200x200, JD79653A, (WFT0154CZB3)
GDEY0154D67 200x200, SSD1681, (FPC-B001 20.05.21)

But how can I find out what display I have, and where's the info on what differs them apart. It sure doesn't say DEPG0150BN anywhere on the display.

The only difference I could notice between the "154D67" ones and my "150BN" is that partial refresh doesn't work if I chose a "154D67" one.

So for the examples in GxEPD2 I can now make things work. But I have run some other examples where these selections are not available. So I need to understand what to adjust, to get the partial update (and other things) to work properly, in those examples.

So, well, my question here is a bit general, I guess - Where can I find information on 1. What display I have (so this doesn't happen with my next shipment of displays), and 2. the difference in how each type of display is setup/used correctly?

Thanks!

2

You can't.

Waveshare doesn't provide information on the panel name and origin, nor on the controller it has.

You can guess, by looking at the marking on the flexible connector. I have added the markings on my panels in the comments of the panel selections.

By selecting the correct driver class in GxEPD2, if the panel is supported.

I need to take a timeout. I will not answer any posts for a while, nor work on displays or e-paper displays.
-jz-

3

Hi JZ

Thanks for your quick response! Sorry to hear you need a timeout, I hope you are ok and that you will have a nice time off from here.

My display says FPC8101 on the flex cable, so definitely the DEPG0150BN then.

Taking another look into the latest datasheet on Waveshares website for their 1.54" inch display (sku:12995) Link to datasheet I notice the active display area is 27 by 27 mm, which is 38.2 diagonal which is 1.50"

So, the 1.54" display from Waveshare actually have a 1.50" active display size. Perhaps this is the reason for the "name" DEPG0150BN.

Which brings me to my final (hopefully) question. Where did you, JZ, get these "names" from? (I am not expecting an answer until after your time out.)

Stay well!

Thomasx
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I think you might find answers if you search for that name in the forum.
Searching in the forum often is a good idea! :smiley:

GxEPD2 Partial update shows scrambled text
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True that. I did search initially, but clearly didn't know what to search for to find the right topics, because when I search now when I know what to search for, I notice others have had the very same problem.

Perhaps making the flex cable designation the main "name" in the selection .h-file would be an idea. Using the "technical name " like DEPG0150BN is just really confusing because it is nowhere else to be found and in this case indicates a different display size than what's stated from the supplier/on the display.

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Unfortunately, several different display models can show the same label on the flex-cable. It's a good clue, but not a unique identifier.

It would be great if display manufacturers consistently identified and marked their hardware, but they just don't..

For context, companies like waveshare don't manufacture the E-Ink displays, only the driver board. The display manufacturers (in this case, DKE group?) do consistently use unique model names for their products, but waveshare has failed to document which model they are using. Often the true model name is printed on the rear of the display panel, but this is little help after the display is glued to a waveshare pcb.

It is not ideal, but using the true manufacturer's model name really is the only consistently meaningful way to distinguish between different revisions.

DEPG0150BNS810.pdf (1.7 MB)

For what it's worth, ZinggJM absolutely has explored ideas like this, and you can still find them in the library code, but the manufacturers have basically made this into a dead-end.

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