Raspberry Pi Pico 2 Pinout: Complete RP2350 GPIO & Power Reference

The Raspberry Pi Pico 2 pinout retains the exact 40-pin physical footprint of the original RP2040 Pico to maintain backward compatibility with existing shields and breakout boards. However, the new RP2350 chip introduces internal architectural shifts—including 48 internal GPIOs (with 26 broken out to pads), a fixed 12-bit ADC, and new High-Speed Transmit (HSTX) routing. Below is the direct hardware reference you need to wire your next embedded project without frying the 3.3V logic rails.

The Complete Raspberry Pi Pico 2 Pinout Reference

The physical board exposes 26 general-purpose I/O pins (GP0–GP22 and GP26–GP28), alongside dedicated power, ground, and debug pads. The RP2350 chip itself has 48 GPIOs, but the remaining pins are consumed internally by the QSPI flash memory, USB PHY, and the new HSTX interface. Use this table as your bench-side cheat sheet.

Source: Official RP2350 Datasheet and Raspberry Pi Pico Hardware Documentation.

Rows People Get Wrong (and How to Avoid Bricking Your Board)

While the RP2350 is a robust chip, the physical Pico 2 board includes power-routing components that do not forgive wiring mistakes. Here are the specific pins that routinely destroy boards or cause phantom bugs on the workbench.

• 3V3_EN (Pin 37): This pin is tied to the Enable pin of the onboard RT6154 buck-boost regulator. If you accidentally pull this to ground, the 3.3V rail collapses instantly. If you are designing a custom carrier board and don't need to control the regulator, leave this pin floating (it has an internal pull-up).
• RUN (Pin 30): This is the RP2350 hardware reset pin. It is active-low. Unlike some microcontrollers that require an external pull-up resistor, the Pico 2 includes an internal pull-up. However, if you are routing this to a physical reset button, keep the trace short to avoid ESD-induced phantom resets.
• ADC_VREF (Pin 35) and AGND (Pin 33): The RP2040 had a well-documented ADC non-linearity bug caused by internal voltage drops. The RP2350 fixes the silicon-level bug, but you still must respect the board-level analog domain. If you are doing precision analog sensing (e.g., load cells), tie AGND to your main GND at a single star-point near Pin 33, and ensure ADC_VREF is clean. Do not draw digital return currents through AGND.
• 5V Tolerance: The RP2350 GPIOs are strictly 3.3V tolerant. Feeding 5V into GP0-GP28 will permanently damage the input pads. Use a bidirectional logic level converter (like the TXS0108E) if interfacing with 5V Arduino shields.

Pico 2 vs. Pico 2 W: Board Variant Mapping

Just as regional electrical codes dictate wire colors, the specific hardware variant of your Pico 2 dictates which GPIOs are actually available to your code. The Pico 2 W integrates an Infineon CYW43439 WiFi/Bluetooth chip, which steals three GPIO pins for its own SPI communication and control routing.

Decision Framework: Choose the base Pico 2 when you need every available GPIO for sensor multiplexing or when building low-power battery devices where the WiFi chip's quiescent current is unacceptable. Choose the Pico 2 W for IoT telemetry, MQTT edge nodes, or OTA (Over-The-Air) update capabilities, but design your PCB shields to avoid routing traces to GP23, GP24, and GP25 to maintain cross-compatibility.

Safe Interpretation When Silkscreen Markings Fade

After a few rounds of rework, flux cleaning, or prolonged exposure to high-ambient heat in an enclosure, the white silkscreen pin labels on the Pico 2 can fade or flake off. Guessing pin identities by counting from the wrong end will result in applying 5V VBUS directly to a 3.3V GPIO. Here is the fail-safe method to identify pins when the board markings are missing.

The Physical Anchor Method

1. Orient the board: Hold the Pico 2 so the micro-USB port is pointing away from you (at the top).
2. Locate Pin 1: Pin 1 is always the top-left pad, immediately to the left of the USB port. Pin 2 is the top-right pad.
3. Counting pattern: Odd-numbered pins (1, 3, 5... 39) run down the left edge. Even-numbered pins (2, 4, 6... 40) run down the right edge.
4. Verify the anchors: Pin 39 (bottom-left) is VSYS. Pin 40 (bottom-right) is VBUS. Pin 38 (bottom-right, one up from VBUS) is GND.

Multimeter Verification (Dead Board Testing)

If the board is unpowered and you need to verify the power rails before applying voltage:

• Find GND: Set your multimeter to continuity mode. Probe the metal shield of the USB port. The shield is tied to GND. Any pad that beeps when probed against the USB shield is a Ground pin (Pins 3, 8, 13, 18, 23, 28, 33, 38).
• Find VBUS (Pin 40): Set your multimeter to diode-test mode. Place the red probe on the USB port's center 5V pin (the rightmost inner pin of the USB connector) and the black probe on the USB shield. You should read a ~0.3V to 0.4V drop across the protection diode. Now, keep the black probe on the shield and touch the red probe to the bottom-right pad (Pin 40). If it beeps or reads near 0V, you have confirmed VBUS.
• Find 3V3 (Pin 36): With the board powered via USB, set the meter to DC Voltage. Black probe on the USB shield, red probe on Pin 36. It must read between 3.25V and 3.35V. If it reads 0V, check if Pin 37 (3V3_EN) has been accidentally shorted to ground.

Bench Tip: When soldering headers to a Pico 2, always solder the corners first, then verify continuity from the USB shield to the GND pins before soldering the remaining 36 pads. This prevents a misaligned header from permanently shifting the pinout map by one row.