The Raspberry Pi Pico W is a powerful and affordable Wi-Fi development board. It features the same RP2040 that was on the original Raspberry Pi Pico, but it also has a Wi-Fi and Bluetooth radio. It's based on the original Raspberry Pi Pico, meaning that all the external 40 pins are pin-for-pin compatible. So you should be able to transfer your projects from one to the other without changing any code.

We're going to take a tour of the board and talk about its features. At the heart of the Pico W is the RP2040 microcontroller, running at 133MHz with 256KB of RAM. It features 30 GPIO, of which 26 are available on the breakout header. There's 2MB of Quad SPI flash for user code and data that you want your code to be able to access. And of course, the thing we're really here for, we have the Infineon wireless interface under this metal can. And this curious pattern on the PCB is the antenna. The wireless interface is an Infineon CYW43-439. This supports wireless LAN, BGN and Bluetooth 5.2. At the time of launch, only wireless LAN is enabled in code, but fingers crossed Raspberry Pi release some drivers for the Bluetooth very shortly.

The debug header has moved from this location to above the wireless interface. And the onboard LED is also now controlled by the wireless interface over SPI. It's not connected directly to a GPIO like on the Raspberry Pi Pico. We have the boot cell button for uploading firmware. And over to the right here, we have the very convenient switch mode power supply, which makes the Pico W really easy to power from batteries. More on that later.

The onboard RP2040 is most commonly programmed in MicroPython, a powerful and simple interpreted language. Although an Arduino port does exist if you would prefer to program in Arduino or C. Let's take a look at the pinout. We can see the GPIO numbering

The Pico W board has a very flexible pinout. Down the sides, just about every group of GPIO pins can be used as some other periphery. This block of four pins can support an entire SPI bus and also provides both of the I2C buses from the RP2040. Additionally, a pair of pins can be used for UART. The left side of the board is very regular and digital only, while the right side of the board has a few more quirks. It has three channels of analog to digital conversion along with the analog ground, and all the power supply pins. The onboard LED is connected to a pin called WL-GPIO0, which will be driven by the wireless interface.

Programmable I/O (PIO) allows users to program their own custom hardware interface. This can be useful for developing code for esoteric or complex chips. PIO interfaces are driven by state machines that operate independently of the main processor. Data can be handed to the PIO controller and have it move data back and forth while the processor does other tasks.

The easiest way to power the PIO is through the onboard USB port. 5V present at this port is also output on VBUS, so power can be drawn directly from the USB connection.

The P.I.O. can be powered through VBUS or VSYS, which is preferred. It can take anywhere between 1.8 to 5.5V into VSYS and will be converted to a stable 3V for the system by the onboard power supply. This means it is easy to power the Pico W directly from alkaline cells, nickel metal hydride cells, or even a single lithium polymer cell. If you intend to still be able to connect USB while there is power present on VSYS from batteries, then it would be best to power it through a Schottky diode, as shown in the datasheet.

The datasheet contains a lot of useful information, such as the mechanical drawing, pinout diagram, advice about how to power your Pico from an external source, and a schematic. For more information, check the resources section at the bottom of the article.