The devices have very flexible interrupt features. The interrupt polarity can be configured to one of three active states. Note, the polarity is the same for both interrupt pins on the MCP23X17. Each pin configured as an input can be individually configured as follows. Interrupt when the pin changes states. For example if no interrupt is pending and an input changes states, an interrupt will occur. The interrupt enable is disables until the condition that caused the interrupt is cleared. This implies that further changes on input(s) will not cause subsequent interrupts. Interrupt when input level is opposite from bit value in associated register (DEFVAL). Again, the interrupt enable is disabled until the interrupt condition is cleared.