Adafruit GreatFET One by Great Scott Gadgets

GreatFET One from Great Scott Gadgets is a hardware hacker’s best friend. At the center is a powerful NXP LPC4330 (Cortex M4 @ 204MHz) with two USB ports, one host and one peripheral, allowing USB interfacing as a 'man in the middle'.

Featuring an extensible, open-source design, it has 100 expansion pins for hacking, making, and reverse engineering. By adding expansion boards called neighbors, GreatFET One transforms into a USB peripheral capable of almost anything, from interfacing with external chips to acting as a logic analyzer or debugger.

The versatile GreatFET One supports programmable digital I/O, serial protocols like SPI, I2C, UART, and JTAG, as well as logic analysis and analog I/O (ADC/DAC). Hi-Speed USB and a Python API allow it to become a custom USB interface to the physical world.

Key features include four LEDs, versatile USB functions including FaceDancer, high-throughput hardware-assisted streaming, and a serial engine. GreatFET One ships in an ESD bag complete with a high-speed USB cable and a wiggler for easy "neighbor" separation.

Designed as a next-generation GoodFET, GreatFET offers enhanced capabilities at a lower manufacturing cost, featuring USB bootloader in ROM for firmware installation without external programming hardware. Though it's more complex to assemble than GoodFET, it's compatible with automated or hand assembly using a soldering iron.