New approaches for in-system debug of behaviorally-synthesized FPGA circuits

This paper present new approaches for in-system, trace-based debug of High-Level Synthesis-generated hardware. These approaches include the use of Event Observability Ports (EOP) that provide observability of source-level events in the final hardware. We also propose the use of small, independent trace buffers called Event Observability Buffers (EOB) for tracing events through EOPs. EOBs include a data storage enable signal that allows cycle-by-cycle storage decisions to be made on an EOB-by-EOB basis. This approach causes the timing relationships of events captured in different trace buffers to be lost. Two methods are presented for recovering these relationships. Finally, we present a case study that demonstrates the feasibility and effectiveness of an EOB trace strategy.