On-chip support for software verification and debug in multi-core embedded systems

The challenges in silicon testing and debug of complex integrated circuits are well understood. Where these circuits include multiple processor cores there is also a dramatic increase in the complexity of verifying and debugging the associated software; with much of this complexity being because of the inherent lack of visibility over internal signals which integration brings. The trend to-date has been to rely upon silicon test interfaces to provide access to internal signals required for software verification and debug. However, it is questionable whether this is sufficient for real-time systems or future designs with increasing processor cores. This study examines the on-chip technology supporting software verification and debug in current designs and proposes enhancements in this area. As much of this technology is primarily intended for silicon test it is lacking in terms of I/O bandwidth, which is a significant limitation for software verification and debug. The authors propose their alternative approach of using an on-chip coprocessor and debug circuitry to address this principal limitation; and describe an embedded application where this approach was successfully applied to monitor timing requirements and detect failures. The authors also outline how this approach could be applied as an architectural solution for formal runtime verification.