Datasheet

There are three GPIO pins from the CYW43439 that are used for other board functions and can easily be accessed via
the SDK:
WL_GPIO2
IP VBUS sense - high if VBUS is present, else low
WL_GPIO1
OP controls the on-board SMPS power save pin (Section 3.4)
WL_GPIO0
OP connected to user LED

NOTE
Full details of the Infineon CYW43439 can be found in the datasheet.
3.9. Debugging
Pico W brings the RP2040 serial wire debug (SWD) interface to a three-pin debug header. To get started using the debug
port see the Debugging with SWD section in the Getting started with Raspberry Pi Pico book.

NOTE
The RP2040 chip has internal pull-up resistors on the SWDIO and SWCLK pins, both nominally 60kΩ.
Raspberry Pi Pico W Datasheet
3.9. Debugging 16