US Patent 7272678 DSP bus monitoring apparatus and method

A bus monitor is provided as a tool for developing, debugging and testing a system having an embedded processor. The bus monitor resides within the same chip or module as the processor, which allows connection to internal processor buses not accessible from external contacts. The monitor uses a separate circular buffer to continuously store, in real-time, data traces from each of one or more internal processor buses. Upon the occurrence of a trigger condition, storage stops and a trace is preserved. Trigger conditions can depend on events occurring on multiple buses and are downloaded via an interface from an external device. Data traces are uploaded via the interface to an external device for evaluation of processor operation.