Changing debug pin for M7

[Azeituno]

Hi all!

I built the Hello World example using SDK_25.12.00_MIMX8ML8xxxKZ and the west build command, but after running it through U-Boot with ext4load, I couldn't see the output in the M7 debug terminal. Is it correct to load it through the U-Boot using ext4load?

Besides that, I'm using the Verdin iMX8M Plus and wanted to know how to set the UART4 as the M7 debug. What is the officially supported way to modify the M7 debug pin?

Thanks in advance.
Lucas Azeituno.

[Chavira]

Hi @Azeituno,

Thank you for contacting NXP Support!

By default, UART4 is used as the debug console on the EVK boards.

It is possible that the issue you are experiencing is related to how the binary is being loaded onto the M‑core. To help us better understand the situation, could you please provide the exact steps you followed to load and run your application on the M‑core?

If a modification to the debug console configuration is required, this can be done in the board.h file, where the UART instance and related settings can be adjusted.

If you share your procedure, we will be happy to review it and guide you through the proper configuration.

Best regards,
Chavira

[Azeituno]

Hi Chavira,

Sorry for the delay.

I copied the binary to the board, rebooted it, and stopped at U-Boot. Then I ran the following command in the U-Boot console:

ext4load mmc 2:2 ${loadaddr} "/home/root/hello_world_cm7.elf"; cp.b ${loadaddr} 0x7e0000 20000; dcache flush; mw.w 0x550ff000 0 64; bootaux 0x7e0000

 It seems to be loaded as expected, but I couldn't see the "hello world" message.

Thanks in advance!

[Chavira]

Hi @Azeituno,

I haven’t tested this using the ELF file.
Please try using the binary (.bin) file instead, as we recommend storing and loading the binary from the boot partition.

You can also refer to our guide based on the EVK board in the link below:

https://www.nxp.com/document/guide/getting-started-with-the-i-mx-8m-plus-evk:GS-iMX-8M-Plus-EVK?sect...

Best regards,
Chavira