Embedded Software Design of ThumbPod

The Thumbpod consists of multiple layers of programming abstraction, as shown in the figure on the right. The top-level software is written in Java on top of the K Virtual Machine. The KVM runs on top of the LEON2 embedded Sparc core. For development purposes we rely on TSIM, an instruction set simulator for LEON2 provided by Gaisler Research. The hardware platform includes a fingerprint sensor and cryptographic acceleration hardware. These low-level hardware features are driven by dedicated support routines in C, which are in turn encapsulated as Java Native Functions.

The underlying principle of this design is that variability of the design is pushed to higher abstraction levels: Programming is easier at higher abstraction levels, therefore we invest some effort in creating a convenient programming model for these low-level features.

In our methodology we use simulation at several abstraction levels, going from simulation at a purely functional level to cycle-true co-simulation of the embedded platform.

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