I realized that P9_11 p9_13 had a beat using my logic analyzer which I think is caused by BONE_LED_P9_11.dts in arm64/overlays/? But I did not include the dtbo file in extlinux.conf and the beat was still there after deleting the file. Or is it caused by the line in extlinux.conf “append console=ttyS2,115200n8” in ttyS2 since uart0 is using the same link?
and…one of the three pin headers is for seeing boot logs while the other one is for a very specific boot log having to do w/ security (I think). Introduction — TISCI User Guide
P.S. I am not sure if UART0 is completely available b/c of the boot log usage dedication. I am sure others that are behind the building of the board will introduce more in time. I am sort of guessing here but familiarity w/ the am335x and UART0 being the debug header makes me think it is similar on this board but I could be severely mistaken.
Thanks for all the help.
So I removed the “console=…” from the kernel command line and also stopped the systemd services. Specifically the serial-getty@ttyS2.service and serial-getty@ttyGS0.service on boot.
I am not sure what to modify in the u-boot. I tried removing the default pins uart0 controls. But I am still getting the console debug output on the pins.