RockPi S with 3.5" SPi Display

#1

I have a Waveshare 3.5" SPI screen, version A

https://www.waveshare.com/3.5inch-rpi-lcd-a.htm

I’d like to use it together with my RockPi S, but I can’t make it working.

overlay and instructions are provided for the version B-v2 and C only, support for old version A is missing.

It’s a pity because if the Waveshare version A will be working, plenty of derivatives based on same controller can be used (I also have few at home)

#2

From waveshare website:

3.5inch RPi LCD (A) and 3.5inch RPi LCD (B) are hardware compatible with each other (uses different driver), and can be mutually substituted in most cases. (A) for low cost ver. while (B) for IPS ver. with better displaying.

Model A and B should be the same, just IPS vs none IPS.

#3

thanks for your reply.

I have two 3.5" touchscreen, one Waveshare 3.5" and one clone. Both of them work fine with other SBCs.

I flashed latest official image (debian-based) on the SD-card, then I enabled the overlay following those instructions:

https://wiki.radxa.com/RockpiS/hardware/display

I have two RockPi S v1.2, so the selected overlay was this one:

rockpis-v12-spi2-waveshare35b-v2

I also modified the config file /etc/X11/xorg.conf.d/20-modesetting.conf, trying with both “/dev/fb0” or “/dev/fb1”.

I did not install any desktop manager, I’d like to see the terminal on the screen. Am I missing something? did someone else tried that overlay with latest image?

#4

paste your kernel dmesg here and send the link.

#5

OK, I’ll do that

on Waveshare website I found this:

Version Update

  • Because of stop production of old LCD, we update 3.5inch RPi LCD (B) to Rev2.0
  • The dimension of LCD is different, and driver is updated as well.(Please download the new driver if you have the new version)
  • You can recognize new and old version by the silk screen printing on the backside. The new version has screen printing Rev2.0

This can explain why my display are not working, I have an old A version, that shares the same driver with B ver1, but not with B ver2

#6

flashed new image and followed procedure from scratch, I can see some text in the screen

this is the dmesg log, just in case

#7

I installed LXDE, outcome is not the best

IMG_20200617_182042
IMG_20200617_182042.jpg2080×1560 1.11 MB

it looks like the color bit depth is very low, it definitely looks better under Raspberry Pi

Any chance to have the overlay for LDC B ver1 on top of the ones for LCD B v2 and LCD C

#8

Hello, with the new update on the chip working only with the Ubuntu focal server i have a hard time setting up any GUI on top. Although using the documentation i can get the display working without a gui, once i install the LXDE or any other ubuntu-desktop i get a blinking cursor at the startup.

Any chance you could drop the steps you followed to get the LXDE installed?