SPI clock not working on pin

[Siddhesh]

Assigning Pin 0.06 as SPI clock on NRF52840 does not work. Is there any limitation on pins which can or cannot be assigned as clock for SPI. This is important to know because we have 2 different peripherals connected over SPI.

[Fredrik]

Are you using the nRF52840 DK? If yes, then P0.06 is used by the UART connected to the interface MCU. See the nRF52840 DK user guide, chapter 6.6.

[Siddhesh]

Yes. That would make sense why it did not work on the DK.
This should not be an issue on a custom design right ?

[Fredrik]

It should work fine on a custom design.

For reference, check out the nRF52840 product specification. "Table 2: QIAA pin assignments" lists all pins, their special purposes and alternate functions. As you can see, P0.06 is listed as General purpose I/O.

[Siddhesh]

Thank you. We had looked at it and then decided on using P0.06 as SCK. The test code did not work on the custom board so tested it on the DK first. I'll recheck my stuff again on the custom board.