The USB Debug Adapter provides the interface between the PC's USB port and the C8051Fxxx's in-system debug/programming circuitry.
This is the compatible version.
The attached 10-pin debug ribbon cable connects the adapter to the target board and the target device's debug interface signals (the USB Debug Adapter supports both Silicon Laboratories JTAG and C2 debug interfaces.) Power is provided to the adapter from the USB connection to the PC; the USB cable is included as part of the USB Debug Adapter. The USB Debug Adapter is capable of providing power to some of the Silicon Laboratories' circuit boards via pin 10 of the debug connector.