nRF52 - OK to leave SWDIO and SWDCLK unconnected

[Charlie Skilbeck]

If I use a breakaway for some debug pads which SWDIO and SWDCLK are connected to and then snap it off so the traces are no longer connected to anything, will this cause a problem? I'd rather not use up space with resistors for pulling them either way if I can avoid it...

[Sigurd]

Hi,

It's OK to leave them unconnected on the nRF52. You don't need any external resistors. As described here, the SWDIO line has an internal pull-up resistor, and the SWDCLK line has an internal pull-down resistor.

Note: On the nRF51 it’s recommend to have an additional 1k ohm external resistor on SWDCLK.

[Charlie Skilbeck]

awesome, I should have seen that, thanks.

[Sami]

Very helpful, thank you!