All actions, whether they are internal or external at the pins, are based on this CPU Clock. That means, each signal is triggered by a specific clock edge.1 Reading the AC Characteristics . 3Figure 1: Multiplexed Bus, Nominal Timing - CPU Clock = f1 3Figure 2: Multiplexed Bus, Nominal Timing - CPU Clock = f2 4Figure 3: Possible Delays of a Signal 6Figure 4: Multiplexed Bus, Real Timing. 7Figure 5: Output, System an Input Delays 8