GreatFET One is a hardware hacker’s best friend. With an extensible, open source design, two USB ports, and 100 expansion pins, GreatFET One is your essential gadget for hacking, making, and reverse engineering. By adding expansion boards called neighbors, you can turn GreatFET One into a USB peripheral that does almost anything.

Whether you need an interface to an external chip, a logic analyzer, a debugger, or just a whole lot of pins to bit-bang, the versatile GreatFET One is the tool for you. Hi-Speed USB and a Python API allow GreatFET One to become your custom USB interface to the physical world.

• programmable digital I/O
• serial protocols including SPI, I2C, UART, and JTAG
• logic analysis
• analog I/O (ADC/DAC)
• data acquisition
• debugging
• versatile USB functions including Facedancer
• high-throughput hardware-assisted streaming serial engine
• four fabulous LEDs!

GreatFET One ships in an ESD bag with a high-speed USB cable and a wiggler for easy separation of neighbors. Enclosures and neighbors are sold separately.

---

Purchasing

GreatFET One is available from:

• Adafruit (US)
• Ada’s Technical Books (US)
• Cool Components (UK)
• Fab.to.Lab (IN)
• Hacker Warehouse (US)
• HackmoD (DE)
• NooElec (US/CA)
• OzHack (AU)
• Passion Radio Shop (FR/UK)
• PiShop.us (US)
• RoboSavvy (UK)
• SparkFun (US)
• VCTEC (KR)
  
  

---

Documentation + Technical Information

GreatFET One is also known by the code name Azalea. For documentation and open source software, visit the GreatFET manual on Read the Docs. For open source hardware design files, see the hardware git repository. Read the latest news about GreatFET One in our GreatFET-tagged blog posts.

---

Background

GreatFET is a next generation GoodFET intended to serve as your custom Hi-Speed USB peripheral through the addition of expansion boards called “neighbors”.

GreatFET is designed to provide a significant step up in capabilities from GoodFET while making the design manufacturable at a lower cost than GoodFET. In addition to being designed for automated assembly, it can be hand-assembled with a soldering iron, though it is a more complicated assembly than GoodFET. An important similarity to GoodFET is that GreatFET has a USB bootloader in ROM, so it is possible to build a board by hand and install firmware onto it without the need of any external programming hardware.

---

Getting Help

The answers to many general questions about GreatFET use and development can be found in the GreatFET manual on Read the Docs.

If you still need assistance after browsing the wiki, please visit issues on the GitHub project. This is the preferred place to ask questions so that others may locate the answer to your question in the future.

We invite you to join our community discussions on Discord. Note that while technical support requests are welcome here, we do not have support staff on duty at all times. Be sure to also submit an issue on GitHub if you’ve found a bug or if you want to ensure that your request will be tracked and not overlooked.

If you wish to see past discussions and questions about GreatFET, you may also view the mailing list archives.