Advanced users • SUCCESS: Recipe for getting RPI5 debug port and GPIO UART working at the same time

Hello folks,

I wanted to share this picture of a working setup, with an RPI5, a GPIO breakout board, a flat ribbon and two debug probes.

Dmesg:
[ 0.411147] 1f00030000.serial: ttyAMA0 at MMIO 0x1f00030000 (irq = 125, base_baud = 0) is a PL011 AXI

I've tested it to minicom -b 921600 -o -D /dev/ttyAMA0



You can see in this picture that I have the debug cable for GPIO pins 14 & 15 wired such as to have the Black wire to position 13, then the Yellow wire on position 14 and the orange wire on position 15.... The documentation states that Yellow is RX and Orange is TX... however, it makes sense that they be swapped where the Orange coming from the probe being TX...goes to pin 15 on the breakout board which is RX and similarly Yellow coming from the probe which is RX goes to pin 14 on the breakout board which is TX...

There is nothing in the config files required to get the GPIO working, nor anything with PINCTRL, etc.

All I modified was adding console=serial0,115200 to the boot config.

Now, I have two minicom sessions running at the same time on my Ubuntu PC, each connected to a separate debug probe, one seeing the debug header working on /dev/serial0 and and the other pumping data at 921600 bps onto /dev/ttyAMA0

It ought to be easier to get to this point... so I decided to share and place evidence out in the open.

Francois

Statistics: Posted by fmenard1234 — Sun Jan 12, 2025 2:32 am

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