Altmode Friend Easily Adds USB-C PD to Any Project

RP2040-powered building block for managing Power Delivery.

James Lewis
1 year ago β€’ HW101

For end users, the USB's Power Delivery (PD) specification means a single power supply can efficiently power small or large devices. This flexibility is because the spec enables a power supply (source) and device (sink) to communicate their capabilities and requirements to negotiate the best option for delivering power. Unfortunately, incorporating PD into a project is more complex than a couple of resistors, like with previous generations of USB. Thankfully, drop-in modules like the Altmode Friend add USB PD to any project.

Altmode Friend comes from FairywrenTech. The module's printed circuit board measures 46 millimeters squared and has castellated edges. Castalleted edges and pre-made KiCad footprints mean you can easily add PD support to a project. Alternatively, the spacing of the pads is even breadboard friendly!

The board contains an onsemi FUSB302B front-end chip that negotiates voltage, current, and mode. In USB-C, a device could be a source or sink. With Altmode Friend, an RP2040 microcontroller talks to the FUSB302B to tell it what to negotiate. Additionally, the module contains a two megabyte flash chip. Depending on your project, you could use the RP2040 to drive the entire project AND control the FUSB302B.

One future goal FairywrenTech has for the Altmode Friend is fully MicroPython support. Eventually, you can easily configure Power Delivery options directly in a MicroPython program. Today, the code samples demonstrate configuring the USB PD interface chip over I2C. And if MicroPython is not your development environment of choice, you can program the RP2040 with its C-SDK or the Arduino library.

FairywrenTech also has a development board available to support the Altmode Friend. The dev board contains both through-hole (2.54 mm) and SMD (1.27 mm) pads. The SMD pad spacing makes it easy to prototype with SO, SOT, and SOIC-sized components. Additionally, the dev-board has a 3.3 volt switch mode power supply capable of providing up to two amps.

The Atlmode Friend is available from FairywrenTech's Tindie store for $9 before shipping. The dev-board costs $20, and for an extra $2, you can get the Altmode Friend soldered to the dev board, so you are ready to go out of the box!

James Lewis
Fan of making things that blink, fly, or beep. Host on element14 Presents, baldengineer.com, AddOhms, and KN6FGY.
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