Adding a 3.5" TFT.

[Anna Vahtera]

Hello. I have a couple of Chinese 3.5" TFTs, model MPI3508. I'm trying to get it to work with my Orange Pi 3.

The module supports either connecting via GPIO or HDMI, either is fine for me.

 

I'm using Linux orangepi3 5.4.20-sunxi64 #20.02.1 SMP Mon Feb 17 02:37:37 CET 2020 aarch64 GNU/Linux

 

I'm trying to get it to display the console - no GUI installed, just the console is enough. The module also supports touch, but I don't care about that - I just want to use it as a monitor..

 

If I use HDMI, I can get a picture, but the resolution is all wrong. It's a 480x320 display but because Chinese manufacturers, it reports itself as having a maximum res of 1920x1080, which obviously is unusable (at this resolution each line in the console is about 2 pixels tall - no way to read text).

I've tried following a dozen or so tutorials dealing with changing the resolution via boot.cmd, but up to this point I haven't gotten ANY of the advice to work. 

I've tried all of these lines in boot.cmd (obviously just one at a time):

 

setenv video-mode sunxi64:480x320-24@60,monitor=dvi,hpd=1,edid=0
setenv video-mode sunxi64:480x320-24@60,monitor=dvi,hpd=0,edid=0
setenv video-mode sunxi64:480x320-24@60,monitor=hdmi,hpd=1,edid=0
setenv video-mode sunxi64:480x320-24@60,monitor=hdmi,hpd=0,edid=0
setenv video-mode sunxi64:480x320-24@25,monitor=dvi,hpd=1,edid=0
setenv video-mode sunxi64:480x320-24@25,monitor=dvi,hpd=0,edid=0
setenv video-mode sunxi64:480x320-24@25,monitor=hdmi,hpd=1,edid=0
setenv video-mode sunxi64:480x320-24@25,monitor=hdmi,hpd=0,edid=0
setenv video-mode sunxi:480x320-24@60,monitor=dvi,hpd=1,edid=0
setenv video-mode sunxi:480x320-24@60,monitor=dvi,hpd=0,edid=0
setenv video-mode sunxi:480x320-24@60,monitor=hdmi,hpd=1,edid=0
setenv video-mode sunxi:480x320-24@60,monitor=hdmi,hpd=0,edid=0

setenv video-mode sunxi:480x320-24@25,monitor=dvi,hpd=1,edid=0
setenv video-mode sunxi:480x320-24@25,monitor=dvi,hpd=0,edid=0
setenv video-mode sunxi:480x320-24@25,monitor=hdmi,hpd=1,edid=0
setenv video-mode sunxi:480x320-24@25,monitor=hdmi,hpd=0,edid=0

 

and saveenv at the end of the file.

 

recompiled with 'mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr'

and rebooted twice after any change in the files.

 

Nothing has worked. With HDMI connected it always displays the picture, but with that resolution everything is really small carbage - unreadable.

 

So I disconnected the HDMI and tried via GPIO, but each and every tutorial with these displays deals with fbtft, which apparently has just been removed, so no dice there.

 

I'm okay with either approach: HDMI with resolution set to 480x320, or via GPIO (and of course same resolution, but at least there shouldn't be any auto-detect via that)..

 

armbianmonitor -u: http://ix.io/2fEY

[XFer012]

Necroposting, I know, but just in case someone else googles up this thread as I did.

The MPI3508 3.5" screen is cheap and sold a ton apparently.

 

So the problem is, the display is actually 480x320 but identifies itself as 1024x768 (!), which is not correct as size and not even as aspect ratio (4:3 vs. actual 3:2)

 

Trying to force 480x320 in armbianEnv.txt does not work, the display shows nothing; probably there are no proper timings in the kernel/DTB/whatever for such low an HDMI resolution.

 

So the trick is using 720x480, which is 1.5x the actual resolution. The aspect ratio is correct, the timings are there, and after all it's even quite readable.

 

So in /boot/armbianEnv.txt add:

    extraargs=video=HDMI-A-1:720x480@60
    disp_mode=720x480

 

and then recompile boot.scr:

mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr

 

Display should run fine.

 

fbset reports:

 

mode "720x480"
    geometry 720 480 720 480 32
    timings 0 0 0 0 0 0 0
    accel true
    rgba 8/16,8/8,8/0,0/0
endmode

 

which may be added to /etc/fb.modes

 

Hope this helps, despite not being optimal.