nRF54L15 uarte20 available pins

[Nathan Boyd]

Hi All,

The nRF54l15 datasheet (v0.8) notes in section 8.25.12 under "Configuration" that UARTE20 can use dedicated pins on P2, but there is no clarification that I can find about which pins are available.

I would like to know if the TRACE pins on Port 2 can be used for UARTE20. I have tried to use them, but without success. Other port pins are working fine.

What I would like to know is:

1. Is Port 2 actually available for UARTE20? OR is the datasheet in error?
2. If Port 2 is available for UARTE20, which pins are mapped?

Regards,

Nathan.

[runsiv]

Hi

As stated in the datasheet "

UARTE20/21	Can use any pin on P1. Can connect across power domains to dedicated pins on P2."

Cross power-domain notes

Selected pins of P2 can be used for some serial interfaces in the peripheral domain — SPIM, SPIS, and UARTE. This is not the most power-efficient way of connecting these serial interfaces, but adds flexibility when designing a circuit board. When setting up the peripheral's PSEL register for cross-domain connections, it must be connected only to the corresponding function listed in the pin assignments table. For example, the peripheral's PSEL.SCK register must use the P2 SCK pin from the pin assignment table. The pin assignments table shows which pins can be configured for cross power-domain connections.

The following pins are available for UART

P2.00

P2.02

P2.04

P2.05

P2.07  

P2.08

P2.09

P2.10

On the DK the following pins are in use, but this can be changed in the devicetree. 

Regards

Runar

[Nathan Boyd]

Thanks Runar.

I have tried to use P2 pins for uarte20 with no success, but I was able verify that uarte20 was working on P1. 

Our hardware is very directly based on the DK. We were planning to use the trace pins for a factory configuration/test UART interface. This would only be enabled for factory use, so we aren't worried about power consumption.

I created the board def for our hardware myself. It is mostly the same as the DK configuration. Looking at the table of the DK pinouts for P2 again, I'm wondering if perhaps I have left some LED functionality enabled which is interfering with the uarte20 operation.

I have checked (via board def and live debugging view of peripheral registers), and can't find anything else using the desired pins (P2.07 and P2.08). I'm building secure and without bootloaders to rule out any peripheral problems.

I will review the board def, and post it here if if I don't find the problem.

In the meantime, is there anything else you can think of for me to check?

Thanks,

Nathan Boyd,.

[Nathan Boyd]

Hi Runar,

I reviewed all the information, and found that our device assignment was incorrect, and the pins we wanted to used for uarte20 were only available for uarte21. Changing the peripheral used fixed the issue.

Regards,

Nathan Boyd.