On using lossless compression of debug data in embedded logic analysis

The capacity of on-chip trace buffers employed for embedded logic analysis limits the observation window of a debug experiment. To increase the debug observation window, we propose a novel architecture for embedded logic analysis based on lossless compression. The proposed architecture is particularly useful for in-field debugging of custom circuits that have sources of nondeterministic behavior such as asynchronous interfaces. In order to measure the trade off between the area overhead and the increase in the observation window, we also introduce a new compression ratio metric. We use this metric to quantify the performance gain of three lossless compression algorithms suitable for embedded logic analysis.