Raspberry Pi Pico WH (Wireless with Headers)

The Raspberry Pi Foundation revolutionized single-board computing with the Raspberry Pi, and now they aim to do the same for microcontrollers with the Raspberry Pi Pico WH. This affordable microcontroller board features their powerful new RP2040 chip, making it ideal for IoT embedded electronics projects at a budget-friendly price.

The Raspberry Pi Pico WH enhances the Pico platform by adding WiFi and Bluetooth Low Energy (BLE) capabilities (BLE support coming soon) while maintaining full pin compatibility with its predecessor.

The Pico WH is similar to the classic Pico but includes pre-soldered headers, a new 3-pin debug connector, and an onboard single-band 2.4GHz wireless interface (802.11n) powered by the Infineon CYW4343 chip. Key features of the 2.4GHz wireless interface include:

802.11n single-band WiFi with WPA3 and Soft Access Point supporting up to 4 clients

Bluetooth Low Energy (hardware capability, software support coming soon)

Connection via SPI to the RP2040 microcontroller with a MicroPython driver for wireless functionality

Due to pin limitations, some wireless interface pins are shared with other exposed pads:

SPI CLK shares with VSYS monitor; VSYS can be read via ADC when no SPI transaction is in progress.

Infineon CYW43439 SPI DIN/DOUT and IRQ share one pin on the RP2040; suitable for checking IRQs only when no SPI transaction is in progress.

Typical interface speed is 33MHz.

For optimal wireless performance, ensure the antenna is in free space, away from metal objects that can reduce performance.

The Pico WH comes with soldered headers for breadboard or perfboard use or can be directly soldered onto a PCB. It features 20 pads on each side, including GPIO and ground pins. All GPIO pins use 3.3V logic and are not 5V-safe. The board provides 25 GPIO pins, 3 of which can be analog inputs (one ADC is not broken out). There are no true analog output (DAC) pins.

The slim green board includes minimal circuitry to get you started:

5V to 3.3V power supply converter

Green LED connected to the wireless module

Boot select button

RP2040 chip with dual-core Cortex M0

Wireless chipset with antenna

2 MB of QSPI flash storage

The RP2040 features a 'permanent ROM' USB UF2 bootloader, allowing easy firmware updates by holding down the BOOTSEL button while connecting to USB or grounding the RUN/Reset pin. This will make the board appear as a USB disk drive for firmware updates.

Key features of the RP2040 chip include:

Dual ARM Cortex-M0+ @ 133MHz

264kB on-chip SRAM in six independent banks

Support for up to 16MB of off-chip Flash memory via dedicated QSPI bus

DMA controller

Fully-connected AHB crossbar

Interpolator and integer divider peripherals

On-chip programmable LDO for core voltage generation

2 on-chip PLLs for USB and core clocks

30 GPIO pins, 4 of which can be used as analog inputs

Peripheral support includes:

2 UARTs

2 SPI controllers

2 I2C controllers

16 PWM channels

USB 1.1 controller and PHY with host and device support

8 PIO state machines

The RP2040 also boasts a unique PIO state machine system, enabling custom hardware logic and data processing without occupying the CPU. This is useful for tasks like NeoPixel control, I2S audio, LED matrix displays, and more.

Software support is robust, with great C/C++ support, an official MicroPython port, and a CircuitPython port. CircuitPython is recommended for beginners due to its ease of use and extensive support for various drivers and sensors. At launch, only MicroPython has WiFi support.

For Arduino usage, the Philhower Arduino core is recommended, providing extensive peripheral support.

The RP2040’s 264KB RAM is complemented by 2MB of external QSPI flash on this board, shared between the running program and file storage for MicroPython or CircuitPython. When using C/C++, the entire flash memory is available, while Python leaves about 1MB for code, files, and other resources.