Adafruit CP2105 Friend adds dual UART over USB-C without hub
Key Takeaway
Adafruit released a USB-C breakout board built around the Silicon Labs CP2105 that exposes two independent UART ports through a single USB connection.
Summary
The CP2105 Friend is a fully assembled breakout board that provides two UART interfaces—one 'enhanced' and one 'standard'—over a single USB-C connection. It requires no USB hub and enumerates both ports automatically when plugged in. The board ships with header pins for breadboard use and works without drivers on Linux.
Port capabilities and board layout
- Enhanced port: 5-8 data bits, 1/1.5/2 stop bits, odd/even/mark/space/no parity, 300 bps to 2.0 Mbps, 320-byte buffers, CTS/RTS/DTR/DSR/RI signals
- Standard port: 8 data bits, 1 stop bit, even/odd/no parity, 2400 bps to 921600 bps, 288-byte buffers, CTS/RTS/DTR/DSR/RI signals
- Pre-blown fuse: Modem signal fuse is already programmed, so control signals work immediately but cannot be repurposed as GPIO
- Physical layout: Enhanced port pins on left side, Standard port on right side; bottom row has minimal RX/TX + power only
- No LEDs or extra GPIO pads compared to CP2102N Friend
- Driver support: Native on Linux, Windows Update auto-install, SiLabs drivers for macOS
Why it matters
The CP210x series' strong Linux driver support and higher speed stability compared to CH340 makes this a practical choice for developers working with dual serial devices on open-source platforms.
Original reference: blog.adafruit.com →