Abmvk
Posts: 272
Joined: Sat Feb 04, 2023 10:07 pm
Location: Netherlands

DSI screen + 2 x HDMI, is it possible & useful?

Wed Feb 21, 2024 11:32 am

I tried to find the answers in the official Pi documentation, on this forum, I asked the people at Pimoroni, and I have tried and failed with an adafruit-screen on the GPIO, but I could not find the answer I was looking for :shock:

I have a RPi 400 and a 5, with two monitors connected to the two HDMI-ports. That works as expected. But I would like to add a mini-screen. The adafruit-screen I tried was connected to the GPIO and worked (on my Pi 400), but I could only configure it to replicate what was on the HDMI-monitors, or work without those monitors. Since that try I moved from 400 to 5. On the 5 I can use both HDMI-monitors again, and I have access to the two CSI/DSI-ports. What I would like to try now is connect a DSI-screen. But only if it can be used independently of the HDMI-monitors.

So, the main screen would be the two HDMI-monitors, and the DSI-screen would be used as a separate output screen. I don’t know what to use it for exactly, I am at the moment just interested in if it is even possible. Let’s say, just for the idea, that the extra screen could show the time, while the main screen is used for normal use.

I would imagine this should be possible, but the fact the people at Pimoroni are not sure, and the fact that a DSI screen is not that cheap, makes me want to check first :)

Any advice or opinion would be appreciated!

aBUGSworstnightmare
Posts: 9666
Joined: Tue Jun 30, 2015 1:35 pm

Re: DSI screen + 2 x HDMI, is it possible & useful?

Wed Feb 21, 2024 1:07 pm

a Pi4/Cm4/Pi400 can drive 3 screens

a Pi5 can drive 5 screens

so HDMI + HDMI + DSI is no problem at all - neither on Pi4 nor on Pi5.
Image
big screen is on DSI

There is no DSI interface on Pi400 --> you can only use 2x HDMI + DPI there
Image
bottom left screen is on DPI

will not speak about the possibility of adding a number of SPI displays...
Abmvk wrote: The adafruit-screen I tried was connected to the GPIO and worked (on my Pi 400)
No information on the product in question equals no answer to be expected!

Abmvk
Posts: 272
Joined: Sat Feb 04, 2023 10:07 pm
Location: Netherlands

Re: DSI screen + 2 x HDMI, is it possible & useful?

Wed Feb 21, 2024 4:08 pm

aBUGSworstnightmare wrote:
Wed Feb 21, 2024 1:07 pm
a Pi4/Cm4/Pi400 can drive 3 screens

a Pi5 can drive 5 screens

so HDMI + HDMI + DSI is no problem at all - neither on Pi4 nor on Pi5.
Image
big screen is on DSI

There is no DSI interface on Pi400 --> you can only use 2x HDMI + DPI there
Image
bottom left screen is on DPI

will not speak about the possibility of adding a number of SPI displays...
Abmvk wrote: The adafruit-screen I tried was connected to the GPIO and worked (on my Pi 400)
No information on the product in question equals no answer to be expected!
Correct about the last one. I have found peace with the fact the adafruit-screen will not work :)

But one more question about the HDMI+DSI setup. I noticed that in your photo the small screens look like they repeat the big screen, did I see that correct? And can they behave independently ?

aBUGSworstnightmare
Posts: 9666
Joined: Tue Jun 30, 2015 1:35 pm

Re: DSI screen + 2 x HDMI, is it possible & useful?

Wed Feb 21, 2024 5:48 pm

Abmvk wrote:
Wed Feb 21, 2024 4:08 pm
..
But one more question about the HDMI+DSI setup. I noticed that in your photo the small screens look like they repeat the big screen, did I see that correct? And can they behave independently ?
Look at the picture with the big + 2 small screens. You should notice that it's an extended desktop (as windows were placed on the screen borders).

The other picture is also extended, but there is no easy way for selecting a background for screen #3 (in the appearance settings you can only select #1 and #2). If you would have looked closely you would have noted that the panel is only on one of them --> not cloning!

Abmvk
Posts: 272
Joined: Sat Feb 04, 2023 10:07 pm
Location: Netherlands

Re: DSI screen + 2 x HDMI, is it possible & useful?

Wed Feb 21, 2024 9:13 pm

I stand corrected. Thank you!

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