Memory elements like flip flops often have additional features such as PRESET or PRECLEAR which can overide their normal operation and force the element into a set or cleared state.
Sanity circuits may make use of these features to force a state machine into a specified initial state on power up. Figure 77 shows one such sanity circuit.
The SANITY signal is active for a time period until the capacitor voltage reaches a certain level, and then becomes inactive. While SANITY is active, the state machine is reset to the desired initial state.
ANU Engineering - ENGN3213
