Pros

• Affordable as heck. At $10, it’s worth grabbing one just to try out.

• Simultaneous SWD and UART operation. This is REALLY convenient.

• Compact. It’s tiny! And so are the mating connectors on a target board. The JST target connectors for the target board are much smaller than rows of 0.1” headers.

• Keyed connectors. JST connectors have an advantage that no row of 0.1” is born with: there’s no way to plug them in backwards.

• Dogfooded solution. Matching debug connectors on the RPi5 indicate that this probe was likely the debugger of choice for the Raspberry Pi bringup team.

Cons

• No dedicated Reset line. Annoying if you’re working with something like a low power device, where reset is generally used to enter a debug mode. (Debug pins are frequently hi-Z’ed to save power.)

• No power to debug target. An obvious tradeoff in favor of a more compact target connector. Annoying because many embedded targets could easily be powered for less than 50mA.

• 3.3V IO only. Another annoying tradeoff - this time for simplicity’s sake. Adding 1.8V support requires all sorts of debugger side complexity like target voltage detection and level shifting. Likely a worthy trade, given that 3.3V IO is a reasonable default across embedded platforms.

• USB Micro, rather than USB-C. I hate USB Micro. It’s tiny and fragile. USB-C adds a degree of surface mount robustness that Micro lacks.