HDMI 7" 800x480 Display Backpack - Without Touch - No EDID

EL Wire/Tape/Panels, LEDs, pixels and strips, LCDs and TFTs, etc products from Adafruit

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
hasan__
 
Posts: 2
Joined: Tue Jan 26, 2021 11:11 am

HDMI 7" 800x480 Display Backpack - Without Touch - No EDID

Post by hasan__ »

Hi,

I am testing a recently bought "HDMI 7" 800x480 Display Backpack - Without Touch" module.

After connecting it to the raspberry pi and editing the config.txt file (as mentioned here: https://learn.adafruit.com/adafruit-5-8 ... -pi-config), it works fine. However, the EDID information is invalid. See the results of the following commands:
$: tvservice -d edid
Writtten 256 bytes to edid
$: od -t x1 edid
0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
*
0000400
$: edidparser edid
Enabling fuzzy format match...
Parsing edid...
HDMI: bad EDID header ff ff ff ff ff ff ff ff
edidparser exited with code -1

When the display is connected to a dell laptop, nothing shows up and the EDID information is not valid either.
See "dmesg" output after connecting the display to the laptop.
laptop_output
laptop_output
1.png (30.35 KiB) Viewed 281 times
When the display is connected to a Jetson nano dev board, the screen is either white or shows the desktop environment but with flickering horizontal lines. The kernel (L4t 32.5) can't read the EDID as well, and uses a fallback edid.
See "dmesg" output after connecting the display to the nano.
nano_output
nano_output
2.png (10.08 KiB) Viewed 281 times
The goal is to get it working on the nano. Could you confirm that the EDID EEPROM was not flashed correctly?

I also tested multiple HDMI cables.

If you need extra debug information, I am available.

Thank you.

User avatar
adafruit_support_carter
 
Posts: 29056
Joined: Tue Nov 29, 2016 2:45 pm

Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED

Post by adafruit_support_carter »

To rule out it being something with that linux utility, can you try using it with some other video source - like another PC.

User avatar
hasan__
 
Posts: 2
Joined: Tue Jan 26, 2021 11:11 am

Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED

Post by hasan__ »

When connected to a different PC, the screen works, but 'xrandr --verbose' doesn't show the EDID as well.
Here is "dmesg" output when booting with the display connected to the PC. Same message shows up when connected after boot.
different_PC_output
different_PC_output
3.png (27.39 KiB) Viewed 271 times

User avatar
adafruit2
 
Posts: 22111
Joined: Fri Mar 11, 2005 7:36 pm

Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED

Post by adafruit2 »

it could be you got a blank one, do you want the EDID info to write?

Code: Select all

0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x04, 0x81, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00,
0x01, 0x11, 0x01, 0x03, 0x80, 0x0F, 0x0A, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x80, 0x0C, 0x20, 0x80, 0x30, 0xE0, 0x2D, 0x10, 0x28, 0x30,
0xD3, 0x00, 0x6C, 0x44, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17,

User avatar
cesvar_
 
Posts: 5
Joined: Thu Sep 09, 2021 1:58 pm

Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED

Post by cesvar_ »

Hi I'm having the same issue at hasan__

I'm able to use the 7" display just fine on an RPi4 using the config settings int he Adafruit guide, but when I used the Nvidia Jetson Nano I only get a blank screen. When using two displays to verify that the Jetson is displaying output properly it does register that there is a second display, but confusingly it reads it as a 40" screen rather than a 7"...

I'll note that when I used the 7" display during set up, it worked just fine, it was only after set up was complete and I was taken to the home Desktop that the display started to have issues.

I'm not too well versed with these devices, so I'm not too sure how to even approach trouble shooting. Would appreciate any info people might have on troubleshooting.

User avatar
adafruit2
 
Posts: 22111
Joined: Fri Mar 11, 2005 7:36 pm

Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED

Post by adafruit2 »

does it work on your windows or mac computer?

Locked
Please be positive and constructive with your questions and comments.

Return to “Glowy things (LCD, LED, TFT, EL) purchased at Adafruit”