What are the max values of resistors /capacitors that can be connected to PA13 and PA14 so the SWD debug is still working? I cannot find the info in any documentation.

[TDK]

I think the best approach is to minimize capacitance and see what works. The clock is configurable and can be slowed down, so unless you load a ridiculous cap on the line, you’ll be able to find a speed at which it works.

nucleo boards have a 22 ohm inline resistor.

[DStan.2]

What about resistors, will an 1k resistor from pin to ground affect the debugging SWD functionality? Is there any documentation on what can be attached to the pins and still work?

[Tesla DeLorean]

Use some common sense, the signalling is on the order of 4 MHz, don't stick an RC circuit on the pins that will impeed usages.

No particular need for strong pullups either, just increases current.

What is your secondary use case for the pins?

What part are we talking about?​

[TDK]

> Is there any documentation on what can be attached to the pins and still work?

I don't think you're going to find documentation for non-standard uses of these pins. There is general GPIO pin frequency characteristics listed in the datasheet. You can use that to guide your decisions.

[DStan.2]

I'm planning to use an stm32L011; the intended application for the pins are driving indication LED's. I assume 1k in series with an led is ok, but lack of documentation in this regard is a bummer. I'm used to atmel specs, and for debugging and programming they have clear indications on what you can stick to the programming pins so they still work.