USB-Cereal

USB-Cereal is a debugging and development tool for designs that use USB-C port and bring out serial TX/RX lines into SBU1/2 pins. USB-Cereal is made compatible with both 1.8V and 3.3V signalling.
A few important things to note:

• USB-Cereal is not an officially supported Google product.
• USB-Cereal will not work as a USB-C hub/splitter. It is a development tool.
• USB-Cereal device is not USB-C spec compliant tool. It will not work with and might damage target devices that hasn’t been designed to work with USB-Cereal. Please use with caution and at your own risk.

Please read getting started before plugging in the device. If used without caution, both USB-Cereal and target device could be damaged.

Getting Started

1. Determine correct serial signalling level on the target device – 1.8V or 3.3V. Incorrect voltage setting might permanently damage your device!
2. Determine correct orientation – top vs. bottom – the tool operates correctly only when SBU1 pin corresponds to TX and SBU2 pin corresponds to RX.
3. Serial log capture – please install ftdi232r drivers. Use your favorite serial monitoring console on the PC.

Avoid Damaging Target Device

USB-Cereal can operate both with 1.8V and 3.3V logic level systems. The transition from 1.8V to 3.3V is NOT automatic and is done via on-board DIP switch. Incorrect logic level setting might cause target device or USB-Cereal failure and/or permanent damage. If unsure of target device logic levels used, always start with 1.8V to avoid damaging the target device. USB-Cereal implements overvoltage clamp transistors, and is unlikely to get damaged from small overvoltage events.

Source Files

1. Schematic diagram + board layout (Altium)
2. Enclosure (STLs, STEP file exported from Autocad Fusion 360)
3. No firmware/programming is required

License

This project is licensed under the Apache v2.0 License – see the LICENSE.md file for details

Contributing

Thank you for your interest – please review CONTRIBUTING.md!