A sequence diagram, illustrating the behavior of the Or1ksim wrapper and its interaction with the quantum keepers for the design is shown in Figure 9.3. Only the operations of the wrapper and quantum keepers are sown, since there is no significant change in the interactions of the UART and terminal (see Section 7.1.2).

Where before, calls to wait were used to enforce synchronized timing, this time the sync function of the ISS gatekeeper is used to ensure a consistent view of time. Rather than being held in strict synchronization, the threads are allowed to catch up at least at each system global quantum boundary.

Figure 9.3.  Sequence diagram for the Or1ksim SoC with decoupled timing, showing interaction with the quantum keepers.