GxEPD2 GDEY1248Z51 (uc8179) - How to start?

Other Hardware Displays
1

Hi @ZinggJM ,

we had a small discussion about parallel panels - I did some more research. And found this product: https://x.alibaba.com/AwHoY4?ck=pdp

It’s quite cheap - 140$ exluding shipping.

I want to ask how should I start. It uses an esp32 board and I found out the pinout (I got it from GooDisplay):

int EPD_W21_SDA = T0; 
int EPD_W21_SCL =T1;
int EPD_W21_CS_S2 = T2; 
int EPD_W21_CS_M1 = T3; 
int EPD_W21_RST_M2 = T4; 
int EPD_W21_RST_M1 = T5; 
int EPD_W21_DC_M2 = T6; 
int EPD_W21_DC_M1 = T7; 
int EPD_W21_CS_M2 = T8; 
int EPD_W21_CS_S1 = T9;  
//BUSY 
int EPD_W21_BUSY_M1=A3;

Which example should I use if I order this panel + controller. The only problem I see is that the esp32 doesn’t have enough ram to handle such high resolution screen. I think the best way would be to download the whole image to the spiffs and write it to the panel.

Happy to hear your thoughts!

2

Per the data sheet it supports
Data 0x3F40_0000 0x3F7F_FFFF 4 MB External Flash Read
Data 0x3F80_0000 0x3FBF_FFFF 4 MB External SRAM Read and Write
If that is not enough you can go to memory banking.
This link will give you the details on the part. https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf This link goes back to the old days but may be easier to understand: arduino - How can 8-bit processor support more than 256 bytes of RAM? - Electrical Engineering Stack Exchange

3

Hi @gilshultz ,

I know that the esp32 has support for PSRAM. I also used boards with PSRAM. But I guess here the board doesn’t have psram.

So that’s why I asked @ZinggJM - if I should download the whole image to SPIFFS / NVS and write it as whole to the panel.

Edit: And how to general start with the library with the panel. I am not a complete beginner I built already esp32 projects but never touched displays.

4

Yes, if you want to present bitmaps or BMP files, this is the option of choice.
GxEPD2 has an example GxEPD2_Spiffs_Example.ino.

Take a look at GxEPD2_1248c.h.
And to your surprise, see:

// Panel: GDEY1248Z51 : https://www.good-display.com/product/422.html
// Controller: UC8179 : https://v4.cecdn.yun300.cn/100001_1909185148/UC8179.pdf
// Connection Module : e.g. DESPI-C1248 : https://buyepaper.com/products/connection-board-for-1248-inch-large-eaper-e-ink-display-demo-despi-c1248
// Demo Kit : e.g. DESPI-1248 : https://buy-lcd.com/products/demo-kit-driver-development-board-for-1248-inch-large-eaper-e-ink-display
// Waveshare Kit : https://www.waveshare.com/product/displays/e-paper/epaper-1/12.48inch-e-paper-module-b.htm

This panel is already supported.

Note however that I don't recommend this panel, nor the b/w version, as it uses 4 controllers to drive the TFT layer. The 4 controllers, two masters and two slaves, should run in synch. But this isn't perfect, and is noticeable during refresh.
And I never re-test GxEPD2 with these panels, as a consequence.

GxEPD2 uses paged drawing for graphics on this panel, with 4 pages:

// Waveshare 12.48 b/w/r SPI display board and frame or Good Display 12.48 b/w/r panel GDEY1248Z51
// general constructor for use with all parameters, e.g. for Waveshare ESP32 driver board mounted on connection board
//GxEPD2_3C < GxEPD2_1248c, GxEPD2_1248c::HEIGHT / 4 >
//display(GxEPD2_1248c(/*sck=*/ 13, /*miso=*/ 12, /*mosi=*/ 14, /*cs_m1=*/ 23, /*cs_s1=*/ 22, /*cs_m2=*/ 16, /*cs_s2=*/ 19,
//                             /*dc1=*/ 25, /*dc2=*/ 17, /*rst1=*/ 33, /*rst2=*/ 5, /*busy_m1=*/ 32, /*busy_s1=*/ 26, /*busy_m2=*/ 18, /*busy_s2=*/ 4));

Actual link: Large 12.48 inch E-paper Display Color E-ink Screen, GDEY1248Z51_Good Display (good-display.com)
-jz-

5

@smartielover

If you are looking for a challenge with e-paper displays, something not yet well supported:

9.7-inch and 13.3-inch Parallel Screen Test Board Development Kit, EPDiy_Good Display (good-display.com)

I bought this board, but didn't have time yet to experiment with it.
But I think the library GitHub - vroland/epdiy: EPDiy is a driver board for affordable e-Paper (or E-ink) displays. would be worth to look at.
And this board from Good Display could be a start.

Have fun!
-jz-

6

Hello @ZinggJM ,

thank you for the detailed response. I had a chat with GoodDisplay and the parallel panel looks really Cool especially the refresh rates are impressive. The big downside is that only the panel costs around 250$ without the case without the driver without shipping.

The linked board has the big advantage of the price (200$ incl. shipping).. The only downside I see is the slow refresh rate of 37 seconds. The parallel Display needs only 1second for a full refresh. Is it worth spending 100-150$ more?

I never saw a Pin-Config like that:

int EPD_W21_SDA = T0; 
int EPD_W21_SCL =T1;
...

Can I ignore the T and use only the Numbers behind it? I want to use the controller which comes with the panel. To reduce the time to get this thing working.

The Code from Good-Display streams the Bitmap-Values and send it to the panel. For me it would be enough to download the whole Bitmap and refresh the panel afterwards. I don't want to display realtime-Data a refresh every 2mins would be fine.

I will think about the other options.

7

The link in your first post is pretty useless for me. What shop is it related to?
I order frequently through AliExpress. There I can see the shop that sells the product, and the rating of the shop.

It looks like the display your link relates to might be the 1304×984, 12.48inch E-Ink display module, red/black/white three-color, SPI interface (waveshare.com).
The 3-color displays do have long refresh times.

See arduino-esp32/variants/esp32/pins_arduino.h at master · espressif/arduino-esp32 · GitHub
The T* pins seem to be pins with trigger interrupt capability, so this is unusual name usage.

The Waveshare display comes with the Waveshare ESP32 Driver processor board, as far as I remember.
-jz-

Update:
Color WIFI Tag, 12.48 inch E-paper Display Label Sign, GDP1248RW1_Good Display (good-display.com)
Ok, now I found it. I don't usually look under signage.
Color WIFI Tag, 12.48 inch E-paper Display Label Sign, GDP1248RW1

8

The Link is the official GoodDisplay Shop on Alibaba. The send me the code for the esp32 and the Software for windows.
It includes:

  • Panel
  • Enclousure
  • Driver

They told me 140$ + 60$ shipping .. The other Panel cost without driver + enclosure 250$. The Problem I see here is: Is it worth paying so much more for faster refresh rates...

Thank you for the research with the Pin-Numbering its really weird that they doesn't use the normal numbers.

9

In order to provide better user experience for our 12.48-inch E-paper, we specially launched this GDP1248RW1 module, which is powered by Type-C and supports firmware updates.

I like e-paper displays from Good Display. But I questioned the usefulness of these 12.48" displays.
So maybe this is an attempt to get rid of some surplus panels?

Maybe you should state your motivation for looking for large e-paper displays. What are your needs?

I need to terminate with this response to this topic.

I try to give answers in this forum to questions and issues with my libraries.
But I no longer have time to answer questions in a broader scope.
-jz-

10

Totally understand that your free time is limited. I will do my homework and if I buy this panel I will create a new thread and ping you.

My use case: Displaying data from HomeAssistant, Pictures and other Values...

11

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