J721EXSOMXEVM: How to check board revision

Guillaume Henri

Part Number: J721EXSOMXEVM

Dear Jacinto champs,

Trying here to get the u-boot DFU to work with the USB Type C connector on the J721EXSOMXEVM

Under the u-boot DFU chapter the documentation specifies that :
"This mode is not supported on J721E Rev E2 and earlier boards“

Based on the Revision history in the schematic and schematic header the latest revision should be E8 but how to be sure?

Could you tell how the revision can be checked on the physical board ? Could you send a picture where to look at on the board for instance ?

Thank you!

Best regards,

Guillaume

over 1 year ago

0 Erick Narvaez over 1 year ago

TI__Mastermind 36307 points

Hello Guillaume,

You can check the J721E SOM board revision on the board, it should be printed like this:

See the PCB# which ends in E6 in my case.

Regards,

Erick

0 Mattias Wallin over 1 year ago in reply to Erick Narvaez

Prodigy 50 points

Hi,

Thank you for above answer.

Using your instructions I see that my PCB# ends with 8A on my J7 SOM. Does that mean that my board does not support USB DFU boot mode? Too old boot ROM?

I am following the instruction on this page: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/latest/exports/docs/linux/Foundational_Components/U-Boot/UG-DFU.html where it notes that "This mode is not supported on J721E Rev E2 and earlier boards.". There is nothing on USB (lsusb and dfu-util -l) after setting the dip switches according to above link and power up.

If I have the wrong board (recently ordered) for this, what board should I order?

Regards,

Mattias

0 Erick Narvaez over 1 year ago in reply to Mattias Wallin

TI__Mastermind 36307 points

Mattias,

Can you send the full number? I believe you are on the latest (later than mine).

Let's see what the issue could be. Which USB port are you connected to? It should be the USB-C connector.

Regards,

Erick

0 Mattias Wallin over 1 year ago in reply to Erick Narvaez

Prodigy 50 points

Great, than maybe I can rule that out. I got worried when my u-boot reported board revision "unknown".

The full nr of my J7 SOM is PCB# PR0C078A and on my J7 Common Processor Board it is PCB# PR0C079A.

Yes I use the USB-C connector on the EVM with a USB-C to USB-C cable to my linux host PC. I have checked that my cable and host pc port work by connecting it to a Beaglebone AI64 and it works. For the dip-switches I tried to follow the instructions above.

Regards,

Mattias

0 Mattias Wallin over 1 year ago in reply to Mattias Wallin

Prodigy 50 points

I got the DFU from boot ROM working now. Thanks for pointing out that my rev 8A board was ok to test USB bootstrap with.

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J721EXSOMXEVM: How to check board revision