colin4124
Posts: 3
Joined: Mon Nov 27, 2017 5:42 am

Attaching Display to the Compute Module IO Board by the DISP0 [solved]

Mon Nov 27, 2017 5:58 am

I follow below links and I can attach Raspberry Pi Official 7" Display to the Compute Module IO Board by DISP1 port.
https://github.com/raspberrypi/document ... display.md

Do I connect the display to the DISP0 port on the Compute Module IO board rather than DISP1 ?

I can not found any keyword about DISP1 information in https://github.com/raspberrypi/document ... 1-only.dts .

Could I modify disp1-only.dts file to use DISP0 rather than DISP1? If so, how could I do that?

Thanks.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6422
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Re: Attaching Display to the Compute Module IO Board by the DISP0

Mon Nov 27, 2017 10:43 am

colin4124 wrote:
Mon Nov 27, 2017 5:58 am
I follow below links and I can attach Raspberry Pi Official 7" Display to the Compute Module IO Board by DISP1 port.
https://github.com/raspberrypi/document ... display.md

Do I connect the display to the DISP0 port on the Compute Module IO board rather than DISP1 ?

I can not found any keyword about DISP1 information in https://github.com/raspberrypi/document ... 1-only.dts .

Could I modify disp1-only.dts file to use DISP0 rather than DISP1? If so, how could I do that?
Previously covered - DISP1 only at the moment. viewtopic.php?f=98&t=185141
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

colin4124
Posts: 3
Joined: Mon Nov 27, 2017 5:42 am

Re: Attaching Display to the Compute Module IO Board by the DISP0

Tue Nov 28, 2017 5:48 am

Thanks, I have read the post viewtopic.php?f=98&t=185141 . But it does not update for how to solve this problem.

We designed our own board for CM3 using DISP0 (not knowing about this limitation), too. So, there is no way to enable DISP0 to use Display ?

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Attaching Display to the Compute Module IO Board by the DISP0

Tue Nov 28, 2017 8:05 am

I tried getting disp0 to run and it refused. It seems not to be totally trivial plumbing to get the data flow right.

I may have some more information available, and need to get my cm rig up and running again for something else, so will try and give it another whirl. Gsh said he had it running at one point so it is possible in theory.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

colin4124
Posts: 3
Joined: Mon Nov 27, 2017 5:42 am

Re: Attaching Display to the Compute Module IO Board by the DISP0

Wed Nov 29, 2017 3:31 am

Thanks again. If you do it successfully, please share with me. ^_^

gebervf
Posts: 2
Joined: Fri Nov 09, 2018 8:58 am

Re: Attaching Display to the Compute Module IO Board by the DISP0

Fri Nov 09, 2018 9:11 am

Any updates on this? Some colleagues and I designed our own board to connect and use the CM3. But, we decided to use DISP0 as the interface with the official display (we didn't know about the limitation). Is there any solution to be able to use DISP0 for the display?
Thanks.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6422
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Attaching Display to the Compute Module IO Board by the DISP0

Fri Nov 09, 2018 11:00 am

gebervf wrote:
Fri Nov 09, 2018 9:11 am
Any updates on this? Some colleagues and I designed our own board to connect and use the CM3. But, we decided to use DISP0 as the interface with the official display (we didn't know about the limitation). Is there any solution to be able to use DISP0 for the display?
Thanks.
James appears to have added code that looks for DISPLAY_DSI_PORT in the dt-blob, defaulting to 1 if not present. Merge date was 29 June 2018, so firmware after that should support it.
Try adding

Code: Select all

            [email protected]_DSI_PORT {
               type = "internal";
               number = <0>;
            };
to your dt-blob and see if it works.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

aBUGSworstnightmare
Posts: 1225
Joined: Tue Jun 30, 2015 1:35 pm

Re: Attaching Display to the Compute Module IO Board by the DISP0

Fri Nov 09, 2018 11:15 am

6by9 wrote:
Fri Nov 09, 2018 11:00 am
gebervf wrote:
Fri Nov 09, 2018 9:11 am
Any updates on this? Some colleagues and I designed our own board to connect and use the CM3. But, we decided to use DISP0 as the interface with the official display (we didn't know about the limitation). Is there any solution to be able to use DISP0 for the display?
Thanks.
James appears to have added code that looks for DISPLAY_DSI_PORT in the dt-blob, defaulting to 1 if not present. Merge date was 29 June 2018, so firmware after that should support it.
Try adding

Code: Select all

            [email protected]_DSI_PORT {
               type = "internal";
               number = <0>;
            };
to your dt-blob and see if it works.
That means we can now eiter use DSI0 or DSI1 on custom design with Compute Module? Good to know!

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6422
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Attaching Display to the Compute Module IO Board by the DISP0

Fri Nov 09, 2018 11:24 am

aBUGSworstnightmare wrote:
Fri Nov 09, 2018 11:15 am
That means we can now eiter use DSI0 or DSI1 on custom design with Compute Module? Good to know!
Yes, should be able to.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

gebervf
Posts: 2
Joined: Fri Nov 09, 2018 8:58 am

Re: Attaching Display to the Compute Module IO Board by the DISP0

Mon Nov 12, 2018 11:47 am

6by9 wrote:
Fri Nov 09, 2018 11:00 am
gebervf wrote:
Fri Nov 09, 2018 9:11 am
Any updates on this? Some colleagues and I designed our own board to connect and use the CM3. But, we decided to use DISP0 as the interface with the official display (we didn't know about the limitation). Is there any solution to be able to use DISP0 for the display?
Thanks.
James appears to have added code that looks for DISPLAY_DSI_PORT in the dt-blob, defaulting to 1 if not present. Merge date was 29 June 2018, so firmware after that should support it.
Try adding

Code: Select all

            [email protected]_DSI_PORT {
               type = "internal";
               number = <0>;
            };
to your dt-blob and see if it works.
I've just tested the CM3 with the official Compute Module IO board, having the display connected to DISP0 and changing the dt-blob. It's worked like a charm, both the screen and the touch interface.
Thank you so much!

aBUGSworstnightmare
Posts: 1225
Joined: Tue Jun 30, 2015 1:35 pm

Re: Attaching Display to the Compute Module IO Board by the DISP0 [solved]

Mon Nov 12, 2018 2:32 pm

gebervf wrote: I've just tested the CM3 with the official Compute Module IO board, having the display connected to DISP0 and changing the dt-blob. It's worked like a charm, both the screen and the touch interface.
Thank you so much!
Great news! Thanks for testing/confirming!

Emlich
Posts: 3
Joined: Sun Dec 30, 2018 9:11 pm

Re: Attaching Display to the Compute Module IO Board by the DISP0

Sun Jan 20, 2019 8:47 pm

6by9 wrote:
Fri Nov 09, 2018 11:00 am
gebervf wrote:
Fri Nov 09, 2018 9:11 am
Any updates on this? Some colleagues and I designed our own board to connect and use the CM3. But, we decided to use DISP0 as the interface with the official display (we didn't know about the limitation). Is there any solution to be able to use DISP0 for the display?
Thanks.
James appears to have added code that looks for DISPLAY_DSI_PORT in the dt-blob, defaulting to 1 if not present. Merge date was 29 June 2018, so firmware after that should support it.
Try adding

Code: Select all

            [email protected]_DSI_PORT {
               type = "internal";
               number = <0>;
            };
to your dt-blob and see if it works.
Hello,
I have a similar problem as gebervf. I tried adding the pin_define to the dt-blob as suggested, I compiled it and tried it out, but with no luck. All I am getting on the display is a lot of vertical lines of various colours. Can you please be more specific about the firmware version ? Did you mean firmware version of the display ? I've been using a fairly old one and I don't know how to tell what version it is. Do you think getting a new one could help solve my problem ?
Thank you in advance.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6422
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Attaching Display to the Compute Module IO Board by the DISP0

Mon Jan 21, 2019 10:13 am

Emlich wrote:
Sun Jan 20, 2019 8:47 pm
Hello,
I have a similar problem as gebervf. I tried adding the pin_define to the dt-blob as suggested, I compiled it and tried it out, but with no luck. All I am getting on the display is a lot of vertical lines of various colours. Can you please be more specific about the firmware version ? Did you mean firmware version of the display ? I've been using a fairly old one and I don't know how to tell what version it is. Do you think getting a new one could help solve my problem ?
No, the VideoCore GPU firmware version, as reported by "vcgencmd version". As long as that is reported as after 28 June 2018 (based on my previous post) then it should support being able to select the DSI port number.
Whilst there is a small Atmel processor on the display board, it only translates a few I2C commands and handles the touchscreen.

As first level troubleshooting, does the HDMI display remain active once booted? If so then you have an I2C problem and not a DSI one.
The firmware only supports one primary display.
- First it'll check if a DPI screen has been configured in config.txt, and default to that if defined.
- Next it'll check for the presence of the DSI screen and default to that if found.
- Then it'll try to find an HDMI screen and default to that.
- If no HDMI then it'll drop back to the composite video output (which can't be detected so has to be the lowest priority)

"tvservice -s" will tell you the resolution that has been adopted. The DSI screen should be 800x480, HDMI will be whatever the monitor says it supports, and composite will be 720x480 [NTSC 4:3].
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

Emlich
Posts: 3
Joined: Sun Dec 30, 2018 9:11 pm

Re: Attaching Display to the Compute Module IO Board by the DISP0

Thu Jan 24, 2019 7:23 pm

6by9 wrote:
Mon Jan 21, 2019 10:13 am
Emlich wrote:
Sun Jan 20, 2019 8:47 pm
Hello,
I have a similar problem as gebervf. I tried adding the pin_define to the dt-blob as suggested, I compiled it and tried it out, but with no luck. All I am getting on the display is a lot of vertical lines of various colours. Can you please be more specific about the firmware version ? Did you mean firmware version of the display ? I've been using a fairly old one and I don't know how to tell what version it is. Do you think getting a new one could help solve my problem ?
No, the VideoCore GPU firmware version, as reported by "vcgencmd version". As long as that is reported as after 28 June 2018 (based on my previous post) then it should support being able to select the DSI port number.
Whilst there is a small Atmel processor on the display board, it only translates a few I2C commands and handles the touchscreen.

As first level troubleshooting, does the HDMI display remain active once booted? If so then you have an I2C problem and not a DSI one.
The firmware only supports one primary display.
- First it'll check if a DPI screen has been configured in config.txt, and default to that if defined.
- Next it'll check for the presence of the DSI screen and default to that if found.
- Then it'll try to find an HDMI screen and default to that.
- If no HDMI then it'll drop back to the composite video output (which can't be detected so has to be the lowest priority)

"tvservice -s" will tell you the resolution that has been adopted. The DSI screen should be 800x480, HDMI will be whatever the monitor says it supports, and composite will be 720x480 [NTSC 4:3].
Hello,
thank you very much for your help. It's turned out that I had the pin_define in a wrong version section of the dt-blob. Everything works now.

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