While you cannot legally produce a clone, studying this architecture will make you a better hardware designer. For your own projects, consider using the open-source schematic (which is freely available) or buying an official J-Link EDU Mini to support SEGGER.

VCC_MCU (3.3V) VTref (Target) | | +-------+ +--------+ | | | | [VCCA] [GND] [VCCB] [GND] | | | | +------+-------+------------+--------+------+ | 74LVC8T245 | | A1 (3.3V) <-----> B1 (Target) ----> SWDIO | | A2 (3.3V) <-----> B2 (Target) ----> SWCLK | +---------------------------------------------+ | | [LPC4322] [Target GPIOs Header] Even with a perfect schematic, the J-Link V9 relies on firmware . The LPC4322 contains a bootloader that talks to the SEGGER DLL on your PC. The DLL sends encrypted firmware updates.

If you have been doing embedded development for any length of time, you have almost certainly used a J-Link by SEGGER. The V9 edition (often referred to as the "EDU" or standard version in its era) represents a sweet spot in debugger evolution: it moved away from the older 20-pin parallel port designs toward a modern, high-speed USB 2.0 microcontroller-based architecture.