Rock 3A with MIPI DSI 7" touchscreen

ROCK 3 Series 3A
1

I’m trying to connect a Rock 3A with this screen.

I have tried the instructions from this page but I don’t see anything on my screen. The HDMI output works fine with my standard monitor, so I know the Rock 3A is working.
At the bottom of the display configuration page, it says “Please note that RPI 7’TS need 5V power supply.”
The screen only has the MIPI DSI cable connection. Is there a way to enable the 5V power supply over the MIPI DSI cable, or do I need to supply it from the GPIO pins?

2

I tried to power from the 5VDC GPIO pins and it hasn’t made any difference so far.

Some more details: I’m using the Debian distribution from the Radxa page and in the Display configuration application I only see HDMO-1 as an available display.

I also tried editing the config .txt with each of these lines one at a time without any noticeable change:
dtoverlay=rock-3c-raspberrypi-7inch-touchscreen (original from the linked page)
dtoverlay=rock-3a-raspberrypi-7inch-touchscreen (just a guess)
dtoverlay=rk3568-raspberrypi-7inch-touchscreen (matched the other dtoverlay lines in config.txt)

3

I have BIGTREE TECH Pi TFT 7.0 Display and another 7 inch raspberry compatible display. This display seems to have better quality and one particular thing that was very interesting, is the possibility of switching HOR/VER by hardware.
For this display, the TS works without any changes, but i can’t turn the backlight on.
And for the other, everything works, but i really would like to get this one to work.

@jack , any chance you can get this one and test it on 3A?
I also tested it with radxa raspi driver but kernel crashed.

4

BIGTREETECH Pi TFT7 specifications:

  1. Screen features:
  1. The backlight can be adjusted by a rotary encoder, which is convenient and quick;
  2. One-click rotation display direction function. With a light touch, you can rotate the display
    direction 180 degrees;
  3. On-board studs and positioning posts can fix the Raspberry Pi, which is more integrated;
  4. Use a FPC cable to connect the screen to the Pi’s DSI interface, and the display can be
    touched, which is simple and convenient.
  1. Screen parameters:
    Screen size: 165mm100mm For details, see BTT Pi TFT70 V2.0 -SIZE.pdf
    MCU: HK32F030K6T6
    Screen display area: 154    86mm
    Screen resolution: 800*480
    Number of screen backlights: 27-LED
    Power input: DC 3.3V
    Working method: DSI
    Capacitive touch screen parameters: IC-GT911 structure: G+G

the TS is NOT GT911 but FT56x6.
MCU seems to be working:

[    0.787932] rockpi-mcu: rockpi_mcu_probe: address = 0x45
[    0.787972] rockpi-mcu: send_cmds: 80
[    0.840349] rockpi-mcu: init_cmd_check: recv_cmds: 0xC3
[    1.133256] rockpi_mcu_screen_power_up
[    1.133259] rockpi-mcu: rockpi_mcu_screen_power_up: 
[    1.133272] rockpi-mcu: send_cmds: 8500
[    1.980541] rockpi-mcu: send_cmds: 8501
[    2.833845] rockpi-mcu: send_cmds: 8104
[    2.861095] rockpi-mcu: rockpi_mcu_set_bright: bright = 0xff

I don’t have any RPI to check if the screen display was/is broken.
It’s collecting dust…

well, i missed this error:
[ 0.384909] dw-mipi-dsi fe070000.dsi: [drm:dw_mipi_dsi_bind] *ERROR* Failed to find panel or bridge: -517