Porting e-paper display libraries to another screens

RE: Porting e-paper display libraries to another screens

Amanda Hsieh — Mon, 06 Nov 2023 13:41:47 GMT

HI,

I got some comments from the team. I hope they also can help.

The sequence seems that the panel is using Ultra Chip driver IC UC81xx series.

Zephyr does have the UC81xx series out-of-box driver driver. However, the implementation is monochrome and agnostic to the W/B/R panel.

Zephyr uc81xx driver is here. zephyr/drivers/display/uc81xx.c at main · zephyrproject-rtos/zephyr (github.com)

Sample 4.2" overlay is here. zephyr/boards/shields/waveshare_epaper/waveshare_epaper_gdew042t2-p.overlay at main · zephyrproject-rtos/zephyr (github.com), but it might not be helpful for what you want.

Here is a third-party ported uc81xx driver for a 1.54" panel which supports a W/B/R panel. I think it's a good starting point for them to bring your panel up.code/zephyr/default-firmware/src/epaper_driver · master · electronutlabs-public / papyr · GitLab

Regards,
Amanda H.

RE: Porting e-paper display libraries to another screens

Lorenzo Amicucci — Fri, 03 Nov 2023 07:32:07 GMT

Hi
yes,drivers in zephyr is not trivial. We are in the process to add new learning material.
Meanwhile, I can share this Tutorial about drivers in Zephyr
https://www.youtube.com/watch?v=o-f2qCd2AXo

At the same time, we will check with the engineering team how to support you in this case with this display.

BR
Lorenzo

RE: Porting e-paper display libraries to another screens

Rei Vilo — Thu, 02 Nov 2023 21:49:10 GMT

As said before, the manufacturer does not offer drivers on Zephyr, hence this very thread.

I completed the two fundamental courses on nRF SDK and BLE before considering Nordic SoCs.

I am just surprised by the steep learning curve required by nRF Connect SDK on Zephyr, and the limited resources available.

I will continue the evaluation of the Nordic Semi option and reassess it if needed.

RE: Porting e-paper display libraries to another screens

Lorenzo Amicucci — Tue, 31 Oct 2023 07:47:36 GMT

One additional note: Pervasive Display has public repo with drivers. https://github.com/PervasiveDisplays
It is recommended to use manufacturer drivers and their tools (e.g. tools to generate display images) as each display have slightly different settings.
If you have questions related to Zephyr/nRF Connect SDK (which may be related how to use peripherals or other questions that may show up in relation to the Nordic SDK while porting these third party drivers), or in relation to the ESL application, feel free to open a new ticket. If you never used Zephyr/nRF connect SDK before, you can find here a free course (8h) with all the basics https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/
Please let us know if/where you struggle while trying to use these third party drivers.

RE: Porting e-paper display libraries to another screens

Amanda Hsieh — Mon, 30 Oct 2023 18:15:39 GMT

Hi,

You could refer to https://github.com/NordicPlayground/nrf-esl-bluetooth/blob/edabcb4be1d733f7779a4e8a1009bf471cc6db2d/samples/peripheral_esl/conf/nrf52833dk_nrf52833/nrf52833dk_nrf52833_release_epd.overlay to update the device tree for your EPD.

Please refer to the original manufacturer’s documentation of the panel for selecting the shield board switch positions.

To use EPD other than reference WAVESHARE 250x122, 2.13inch E-Ink raw display panel with the sample, please use the display driver provided by the manufacturer.

-Amanda H.

RE: Porting e-paper display libraries to another screens

Rei Vilo — Mon, 30 Oct 2023 17:28:23 GMT

Standard connections are SPI port and 6 GPIOs.

SPI: SCK, MOSI, MISO
Panel: /CS, /RESET, !BUSY, D/C, POWER
Flash: /CS

RE: Porting e-paper display libraries to another screens

Rei Vilo — Mon, 30 Oct 2023 09:47:36 GMT

Thank you for your prompt answer.

The EPD is the Pervasive Displays E2266JS0C1 2.66" Spectra Red.

A typical refresh sequence looks like

Screen iTC 2.66"-BWR -iH 152x296
SPI at 8 MHz
                 b_reset
         b_sendIndexData [00] 0e
         b_sendIndexData [e5] 19
         b_sendIndexData [e0] 02
         b_sendIndexData [00] cf 8d
         b_sendIndexData [10] 00 00 00 00 00 00 00 00 ... (5624) black page
         b_sendIndexData [13] 00 00 00 00 00 00 00 00 ... (5624) red page
          b_sendCommand8 [04]
              b_waitBusy      HIGH
          b_sendCommand8 [12]
              b_waitBusy      HIGH
          b_sendCommand8 [02]
              b_waitBusy      HIGH
End

with [command] data

RE: Porting e-paper display libraries to another screens

Lorenzo Amicucci — Mon, 30 Oct 2023 09:39:17 GMT

Hi,

In Zephyr, you can find the display driver in https://github.com/nrfconnect/sdk-zephyr/tree/main/drivers/display
there are many epd in the market, with small differences between each other. In most cases, the manufacturer provides the drivers.

Which display do you plan to use? If you could share more details on your display, we can see how to help and give you directions.

thanks
LA