Software simulation of RTL is no longer capable of providing all of the verification required for today’s complex ASIC designs. Modern ASICs are a complex mixture of hardware and software, so it is necessary to verify the design within the context of the complete system, running the full range of software at speeds that approach real-time. Successfully validating an ASIC design on an FPGA-based prototype before committing to silicon is now a key project milestone for most design teams. This paper examines some of the best practices for both successful bring-up and logic debug of ASICs using FPGA-based prototypes.