GxEPD2 1.6.0 Help: Nano ESP32 -> DESPI-C73 -> GDEP073E01

Using Arduino Displays
1

Hi @ZinggJM,

First time working with Arduino, so apologies if I've missed something...

Trying the Hello World example which worked the first time, and not since.
(but the text was blurry and there's a yellow tint now close to the ribbon)

Uncommented these in display_selection_new_style.h:

#define GxEPD2_DISPLAY_CLASS GxEPD2_7C

#define GxEPD2_DRIVER_CLASS GxEPD2_730c_GDEP073E01

And using this to initiate:

display.init(115200);

Pins as per the documentation I think:

BUSY = 7
RES = 9
D/C = 8
CS = 10
SCK = 11
SDI = 13

Any ideas if there's something wrong with the panel?

Code is continuing to be uploaded fine with this in the Serial Monitor:

_refresh : 13891999
_PowerOff : 147000

Thanks in advance!

2

Hi @nparmar , welcome to the forum!

At this time on Sunday evening, just before putting my notebook to sleep, I can only express one quick guess:

Your 3.3V supply may be too weak. I would need to check the Nano ESP32 specs.
With my ESP32 boards, e.g. Wemos Lolin 32, I use a separate LDO for 3.3V (AMS1117) for the bigger e-paper displays.
-jz-

3

Appreciate the quick response on a Sunday, thanks!

Would a UNO R4 perhaps be easier for me to work with as a beginner, given that it operates at 5V?

In the meantime, I'll research how to use an LDO...

4

No, I don't recommend to use an UNO R4 with e-paper displays, as you would need level converters for the connection to the e-paper.

The LDO (low dropout series regulator) is easy to use. It has just 3 connections, Vin, Vout, and GND. You connect 5V to Vin, GND to GND, and get 3.3V on Vout (for a LDO for 3.3V such as AMS1117).
-jz-

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5

Understood, thanks for the clear suggestion.
Will give it a go and report back!

6

No luck even with the AMS1117 I'm using to power the Nano and driver board...

Do I need to do anything to configure the pins in Arduino?
(I believe I'm using the recommended mapping as per the documentation)

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7

Do I understand your posts correctly? You got one refresh of the display the first time, but it didn't look good, and now you don't get any refresh anymore?

The BUSY time for refresh is ok, I had got a value of 12468000us when I created the driver class.

I assume you have measured the 3.3V VCC value, and it was ok?

The display panel has a broad FPC connector, 50 pins, compared to the usual 24 pins of most other SPI e-paper displays. It is important that the connector is fitted well to the DESPI-C73. There is a black lever on the opposite side of the connector, that needs be pulled up before inserting and aligning the flexible connector. And then it needs be pushed down firmly, to get good contact.

I have no other ideas.
But you could run the GxEPD2_Example with your display, and take a look at diagnostic output.
-jz-

8

Yes, that's correct. See below a photo of how the display is currently stuck.

The display ribbon has been firmly fitted into the DESPI-C73 (it perhaps wasn't so well done at the beginning though).

Haven't got a meter to hand to check the valve, but I'll take a look at the diagnostic output in the meantime.

Thanks a lot for your quick assistance over the last few days, very much appreciated!

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9

I forgot to ask if you have checked all your DuPont wires.
I have been lucky so far, only few were bad.
But these are a common source of problems. I happens easily that the isolation is crimped instead of the bare wire.

10

I have replaced all the wires since, but still no change.

Will try out a more basic e-paper (B/W) to experiment with, before returning to this.

Thanks!

11

I finally have tested with Arduino Nano ESP32 myself, and it works (without added LDO).

For the nice picture on Nano ESP I had to modify GxEPD2_Example.ino line 111 to

#if defined(ESP32) || defined(ESP_PLATFORM) || defined(ARDUINO_ARCH_RP2040)

and I uncommented line 223 to keep this picture shown.

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I also tried with USB connected to USB 2 instead of USB 3 on my notebook, but it still worked ok.
-jz-

12

That's great news! Thank you very much for taking the time to test this.

13

Works with another panel that I received this morning.
Thanks so much for your help :slight_smile:

14

Quick note in case it's helpful to anyone else...

Had to add the panel (GDEP073E01) here for all the colours to be displayed in the WiFi example:
bool has_multicolors =