Can I use 2 pins of SWD for debugging?

[JZou.2]

I try to debug H7 MCU by SWD port. Can I only use SWDIO and SWCLK for this? I do not want to use NRST for debug issues.

[Piranha]

No, you need GND also. So that's 3 pins total. 🙂

[Tesla DeLorean]

Sure, but doesnt that limit the experience? Might also consider connecting SWO​

[JZou.2]

Yes, GND also

[JZou.2]

I am not if NRST pin. It seems that SWDIO and SWDCLK can do everything.

[Pavel A.]

.

[Piranha]

Debugging low-power modes without NRST are problematic because once the debug interface is turned off, the debugger is unable to connect and even flash the firmware. And you want to turn off the debug interface to be able to reach current consumption levels lower than few mA.

[Tesla DeLorean]

Is there some space constraint driving you choices here? Getting the signals to a 10-pin SWD connector, or Tag-Connect footprint

If you have other JTAG parts on the board you could also connect those, and do boundary scan on the board.

[JZou.2]

Got it.