16.2.6 Input Threshold Control

The INLVLx register controls the input voltage threshold for each of the available PORTx input pins. A selection between the Schmitt Trigger CMOS or the TTL compatible thresholds is available. The input threshold is important in determining the value of a read of the PORTx register and also the level at which an interrupt-on-change occurs, if that feature is enabled.

Important: Changing the input threshold selection should be performed while all peripheral modules are disabled. Changing the threshold level during the time a module is active may inadvertently generate a transition associated with an input pin, regardless of the actual voltage level on that pin.