  We revisit the AMBA AHB case study that has been used as a benchmark for
several reactive syn- thesis tools. Synthesizing AMBA AHB implementations that
can serve a large number of masters is still a difficult problem. We
demonstrate how to use parameterized synthesis in token rings to obtain an
implementation for a component that serves a single master, and can be arranged
in a ring of arbitrarily many components. We describe new tricks -- property
decompositional synthesis, and direct encoding of simple GR(1) -- that together
with previously described optimizations allowed us to synthesize the model with
14 states in 30 minutes.
