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Raspberry Pi Pico 2 W — Reference & Migration Guide

Source: raspberrypi.com/documentation/microcontrollers/pico-series.html

Hardware Specifications

Spec Pico 2 W (RP2350) Pico W (RP2040)
Chip RP2350 RP2040
CPU Dual-core ARM Cortex-M33 @ 150MHz Dual-core ARM Cortex-M0+ @ 133MHz
Alt CPU Dual-core Hazard3 RISC-V @ 150MHz None
RAM 520KB SRAM 264KB SRAM
Flash 4MB onboard QSPI 2MB onboard QSPI
Wi-Fi 802.11n 2.4GHz (Infineon CYW43439) Same
Bluetooth BLE 5.2 Same
USB Micro-USB 1.1 (device and host) Same
GPIO 26 multi-function pins (same header) Same
ADC 4 external + 1 internal (12-bit) 3 external + 1 internal
SPI 2x SPI controllers (SPI0, SPI1) Same
Security ARM TrustZone, secure boot, OTP None
Dimensions 51 x 21 x 3.9mm Same
Operating temp -20C to +85C Same
Power input 1.8V-5.5V via VSYS, or 5V via micro-USB Same

Pin Compatibility

Drop-in replacement

The Pico 2 W has an identical 40-pin header to the Pico W. All Dilder wiring (e-Paper SPI1, joystick buttons, power) works without any changes. You can swap boards and keep the same wiring.

The GPIO assignments, SPI controllers, and pin multiplexing are the same. Dilder uses the same board_config.h pin definitions for both boards.

Critical Gotchas: RP2350 vs RP2040

These are the issues we hit while porting Dilder. Save yourself the debugging time.

1. BOOTSEL Drive Shows as RP2350, Not RPI-RP2

When you hold BOOTSEL and plug in the Pico 2 W, the USB mass storage drive appears as RP2350 instead of RPI-RP2.

Any scripts or tools that look for RPI-RP2 by name will fail silently. The DevTool and setup.py have been updated to search for both labels.

2. No Hardware RTC

The RP2040 has a hardware Real-Time Clock (RTC) peripheral. The RP2350 removed it entirely.

  • #include "hardware/rtc.h" does not exist on RP2350
  • rtc_init(), rtc_set_datetime(), rtc_get_datetime() are gone
  • pico/util/datetime.h (which defines datetime_t) was also removed

Solution: We created rtc_compat.h in dev-setup/hello-world/lib/Config/ that:

  • On RP2040: includes the real hardware RTC headers (zero overhead)
  • On RP2350: defines datetime_t ourselves and provides software rtc_*() functions using time_us_64()

All 18 program main.c files now use #include "rtc_compat.h" instead of #include "hardware/rtc.h".

The CMakeLists.txt files conditionally link hardware_rtc only on RP2040:

if(PICO_PLATFORM STREQUAL "rp2040")
    target_link_libraries(my_target hardware_rtc)
endif()

3. CMake Cache Poisoning When Switching Boards

If you previously built for pico_w (RP2040) and then try to build for pico2_w (RP2350) in the same build directory, CMake will fail:

PICO_PLATFORM is specified to be 'rp2040', but PICO_BOARD='pico2_w'
uses 'rp2350' which is incompatible.

The CMake cache stores PICO_PLATFORM=rp2040 from the first build. Even if you pass -DPICO_BOARD=pico2_w, the cached platform wins.

Solution: Delete the build/ directory (or use separate build directories per board). The setup.py and DevTool now auto-detect stale caches by checking both PICO_BOARD and PICO_PLATFORM in CMakeCache.txt and wipe the build directory when they mismatch.

4. Pico SDK Version Requirement

The Pico 2 W requires Pico SDK 2.0 or later. Earlier SDK versions do not include pico2_w board definitions.

Check your SDK version:

cat $PICO_SDK_PATH/pico_sdk_version.cmake | grep PICO_SDK_VERSION_STRING

If it says 1.x, update:

cd ~/pico/pico-sdk
git pull
git submodule update --init

5. Compiler Targets Cortex-M33, Not Cortex-M0+

The RP2350 uses ARM Cortex-M33 cores. The GCC flags change from -mcpu=cortex-m0plus to -mcpu=cortex-m33 -mthumb -march=armv8-m.main+fp+dsp. This is handled automatically by the Pico SDK when you set PICO_BOARD=pico2_w -- no manual flag changes needed.

6. Docker Builds Need PICO_BOARD Environment Variable

The Dockerfile was updated to accept a PICO_BOARD env var (defaults to pico_w). When building for Pico 2 W via Docker, pass:

docker compose run --rm -e PICO_BOARD=pico2_w build-sassy-octopus

The DevTool does this automatically based on the board selector dropdown.

Build & Flash Workflow

The workflow is identical to Pico W -- the only differences are the CMake board flag and the BOOTSEL drive name.

Build

mkdir build && cd build
cmake -G Ninja -DPICO_SDK_PATH=$PICO_SDK_PATH -DPICO_BOARD=pico2_w ..
ninja

Flash

  1. Hold BOOTSEL, plug in USB, release
  2. RP2350 drive appears (not RPI-RP2)
  3. Copy the .uf2 file to the drive
  4. Board reboots automatically

Serial Monitor

Same as Pico W -- shows as /dev/ttyACM0 at 115200 baud.

DevTool Support

Select "Pico 2 W (RP2350)" from the board dropdown in the DevTool toolbar. Everything adapts automatically:

  • Flash utility detects RP2350 BOOTSEL drive
  • Build commands use -DPICO_BOARD=pico2_w
  • Docker builds pass PICO_BOARD=pico2_w
  • Pin viewer shows the correct header (identical pins, updated title)
  • Flash size reported as 4MB (4096 KB)
  • All documentation and connection wizard text updates to show Pico 2 W

Setup CLI Support

python3 setup.py --board pico2          # Pico 2 W setup steps
python3 setup.py --board pico2 --step 7  # Jump to build step

The setup steps are identical to Pico W (same SDK, same toolchain) but use the correct PICO_BOARD=pico2_w flag and detect the RP2350 BOOTSEL drive.