The baseline tracking is reset under several conditions. When a baseline tracking is reset, the baseline tracking value is set to the current measured raw_data. If a button is pressed when a baseline tracking reset occurs, the button press will be deasserted. The OUTx pin will immediately be deasserted. A baseline tracking reset can result in reduced sensitivity to subsequent button presses until the baseline tracking returns to 0.

In Figure 5-3, a baseline reset occurs at t=0.6 s. The OUTx button then immediately deasserts. The second button press occurring at t=1.5 s is not detected due to the offset in the baseline tracking. A stronger button press would be detected at t=1.5 s. The third button press at t=2.25 s is detected, as the baseline tracking has returned close enough to 0.

Figure 5-3 Baseline Tracking Reset during button press

Some operations reset the baseline tracking for a subset of channels while other operations reset all channels. Another type of reset is a clear – when the baseline tracking is cleared, a button press will take 2 scan intervals to detect a button press event.