PicoWi Is a Standalone Bare-Metal Wi-Fi Driver for the Raspberry Pi Pico W

Developer Jeremy P. Bentham has written a stand-alone driver for the Wi-Fi radio on the Raspberry Pi Pico W, as part of a project to create bare-metal firmware for high-performance measurement and streaming applications.

“The aim of this project is to provide a fast Wi-Fi driver for the CYW43439 chip on the Raspberry Pi Pico W module, with C code running on the RP2040 processor,” Bentham explains of his work. “It can also be used with similar Broadcom/Cypress/Infineon chips that have an SPI [Serial Peripheral Interconnect] interface, such as the CYW4343W.”

Wi-Fi radio on the Raspberry Pi Pico

Traditionally, the Wi-Fi radio on the Raspberry Pi Pico is handled in firmware — MicroPython or CircuitPython, for most users. Bentham, however, is working on bare-metal applications. And thus needed a driver which could act on its own, without being tied to a particular firmware.

“For simplicity, I use a Raspberry Pi 4 to build the code and program the Pico. With two I/O [Input/Output] lines connected to the Pico SWD [Serial Wire Debug] interface,” Bentham explains. “This is really easy to set up, using a single script that installs the SDK and all the necessary software tools on the Pi 4.”

Bentham’s driver includes sample code for everything from blinking an LED — the traditional hardware “hello, world” — to simple TCP/IP operations, though not everything is supported in the initial release. “For the time being, the code does not support the Access Point functionality within the Wi-Fi chip,” Bentham notes. “It can only join a network that is unencrypted, or with WPA1 or WPA2 encryption.”

More information is available on Bentham’s website, with the source code published to GitHub under the permissive MIT license.

Read More: Jeremy P. Bentham’s PicoWi Is a Standalone Bare-Metal Wi-Fi Driver for the Raspberry Pi Pico W