Mini-Review: WaveShare's RP2350B-Plus-W

An unexpected new from Raspberry Pi was the commercialization, in module form, of the Raspberry Pi Pico W radio circuit. This facilitates the creation of boards compatible with the Pico W.

The board we're looking at here is listed for US$11. Considering that the Pico 2 W is listed at US$7, does the RP2350B-Plus-W have advantages that make it competitive?

Let's start with what the RP2350B-Plus-W has in common with the Pico 2: the pinout on the edges. The physical format is slightly different: on one end, we have a USB-C instead of micro USB; on the other, the antenna extends beyond the end of the board. One absence is where to solder a debug connector.

In addition to the BOOT button, there is a Reset button (an annoying absence in the Pico).

One difference that surprised me is the use of the RP2350B instead of the RP2350A used in the Pico 2. The B model has more I/O pins. One of these pins is connected to an LED (the other LED is connected to the radio module, as on Pico boards). The remaining pins are located on the underside of the board.

The Flash memory is 16 MB, a significant improvement over the 4 MB on the Pico 2. The problem is that the Flash memory is located on the underside of the board, which complicates the use of "castellated" pins (when the board is soldered directly onto another).  Also on the underside, there is a location for soldering a PSRAM.

A difference you won't see in these photos is the radio module's connections to the RP2350. Waveshare chose to use different pins, making the board incompatible with Pico2 W firmwares. The unofficial Arduino package fully supports this board (see here), but there is no support in MicroPython or CircuitPython yet.

My humble opinion is that it was a mistake to make this board in the Pico format, but with differences that make it difficult to use as a direct replacement. A different format (as we've seen in other boards) would facilitate the use of additional pins, the installation of a PSRAM, and the use of castellated pins.