A specific edge case arises when the TIC12400-Q1 is used to detect a wakeup signal that may have already occurred before or during the device startup sequence. Because the first polling cycle establishes the baseline, any INx pin that is already in its "active" state when the first polling cycle completes will have that active state stored as the baseline value. No interrupt will be generated for a transition that was captured as the initial state.

Consider a case where a wake signal drives an INx pin HIGH during the period between power-on and the first polling cycle completing. The TIC12400-Q1 will store HIGH as the baseline for that channel. If the signal is later removed (going LOW), the device will detect the HIGH-to-LOW transition and assert /INT as expected. However, the initial HIGH-to-active transition will have been missed from an interrupt perspective.

To avoid missed wakeup signals in latency-sensitive designs, consider the following:

• Ensure the MCU configures and triggers the TIC12400-Q1 before the expected wakeup signal window. The startup time from TRIGGER bit set to first valid data is 200–400 μS plus one complete polling cycle (e.g., 8 ms at the default setting). Total time from TRIGGER to first valid interrupt is therefore typically less than 10 ms at default settings.
• Read the SWITCH_STATx registers after the first /INT assertion to determine the current state of all channels. If a channel is already in the active state at startup, the application software should respond accordingly rather than waiting for an interrupt.
• Do not rely solely on interrupt-driven handling for wakeup detection. A register read following device initialization provides the ground-truth channel state and should be included in the startup routine.