JAJSFN6G September 2009 – June 2018 TCA8418
PRODUCTION DATA.
A column or row configured as GPI can be programmed to be part of the Key Event Table, hence becomes also capable of generating Key Event Interrupt. A Key Event Interrupt caused by a GPI follow the same process flow as a Key Event Interrupt caused by a Key press.
GPIs configured as part of the Key Event Table allows for single key switches to be monitored as well as other GPI interrupts. As part of the Event Table, GPIs are represented with decimal value of 97 and run through decimal value of 114. R0-R7 are represented by 97-104 and C0-C9 are represented by 105-114
For a GPI that is set as active high, and is enabled in the Key Event Table, the state-machine will add an event to the event count and event table whenever that GPI goes high. If the GPI is set to active low, a transition from high to low will be considered a press and will also be added to the event count and event table. Once the interrupt state has been met, the state machine will internally set an interrupt for the opposite state programmed in the register to avoid polling for the released state, hence saving current. Once the released state is achieved, it will add it to the event table. The press and release will still be indicated by bit 7 in the event register.
The GPI Events can also be used as unlocked sequences. When the GPI_EM bit is set, GPI events will not be tracked when the keypad is locked. GPI_EM bit must be cleared for the GPI events to be tracked in the event counter and table when the keypad is locked.