TWIM transfer doesn't work when using trace data pin P0.18, also cannot use it as a common GPIO pin.

[Petar2635]

Hi,

I have a project which requires using trace data pin P0.18 as an SDA for the sensor, but cannot send

anything because it doesn't generate anything and the program stops at the first TWIM transfer.

I've tried to use it as a GPIO pin but that didn't work either.

My question is:

How to configure the pin P0.18 for it to be usable as a common GPIO without the trace data and SWO functionality?

(I'm using nrf52832 and Nordic SDK 15.2)

I have configured ENABLE_TRACE and ENABLE_SWO as 0, but to no avail (I still get nothing on the logic analyzer).

I have seen the previous questions on:

https://devzone.nordicsemi.com/f/nordic-q-a/59294/i2c-fails-to-work-when-p0_15-p0_16-is-configured

https://devzone.nordicsemi.com/f/nordic-q-a/46110/configure-p0-14-and-p0-15-as-scl-and-sda/181826#181826

but couldn't make it work.

Do you have any suggestions/examples of the solutions for the aforementioned problem?

Any help would be appreciated.

Petar

[Simonr]

Hi

Are you using the nRF52 DK or some custom board? The nRF52 DK uses pin P0.18 as LED 2, and you'll have to cut solder bridge SB6 in order to use the pin header P0.18. Keep in mind that most of our examples have set P0.18 as the LED_2 pin in the board file pca10040.h (located in <SDK FOLDER>\components\boards), which likely conflicts with your configuration of that pin.

Best regards,

Simon

[Petar2635]

Hello Simonr,

I'm using a custom board so that shouldn't be an issue.

The problem is that the pin is stuck at 0 and when I try to change it

program stops. Doesn't continue to the next instruction.

Same code works on the other pins but not on this one.

Is it maybe due to trace data or SWO, I'm using JLink.

[Petar2635]

Managed to toggle GPIO pin 18, but when I use the pin for the TWIM transfer the program crashes.

Do you have any suggestions on how to fix this issue?

[Simonr]

Hi again

Can you describe how exactly your program crashes when using pin P0.18? Have you done any debugging at all to see where the application crashes? And have you made sure that pin P0.18 isn't defined any other places in your project?

Best regards,

Simon