The QUIC_8051_OCD is functionally equivalent to the QUIC_8051 embedded processor core. Besides that, it features an on-core debug module that is accessible though a standard JTAG interface. Because in most FPGA the JTAG interface cannot be used for application a separate JTAG interface is implemented.
While the in-circuit emulator based approach is the most efficient for debugging and leads to the smallest gate count some customers try to avoid the cost for the emulator. They prefer to have a small debug logic on-chip that even resides in the production version of the SoC. QUIC_8051_OCD fits perfectly for these customers.