Testing ThumbPod: Softcore bugs are hard to find

We present the debug and test strategies used in the ThumbPod system for Embedded Fingerprint Authentication. ThumbPod uses multiple levels of programming (Java, C and hardware) with a hierarchy of programmable architectures (KVM on top of a SPARC core on top of an FPGA). The ThumbPod project teamed up seven graduate students in the concurrent development and verification of all these programming layers. We pay special attention to the strengths and weaknesses of our bottom-up testing approach.