MC68HC908JB8 Datasheet, PDF (232/286 Pages) Motorola, Inc – MICROCONTROLLERS

Keyboard Interrupt Module (KBI)
3. Write to the ACKK bit in the keyboard status and control register
to clear any false interrupts.
4. Clear the IMASKK bit.
An interrupt signal on an edge-triggered pin can be acknowledged
immediately after enabling the pin. An interrupt signal on an edge- and
level-triggered interrupt pin must be acknowledged after a delay that
depends on the external load.
Another way to avoid a false interrupt:
1. Configure the keyboard pins as outputs by setting the appropriate
DDRA bits in data direction register A.
2. Write logic 1s to the appropriate port A data register bits.
3. Enable the KBI pins by setting the appropriate KBIEx bits in the
keyboard interrupt enable register.
14.7 Low-Power Modes
The WAIT and STOP instructions put the MCU in low-power
consumption standby modes.
14.7.1 Wait Mode
The keyboard module remains active in wait mode. Clearing the
IMASKK bit in the keyboard status and control register enables keyboard
interrupt requests to bring the MCU out of wait mode.
14.7.2 Stop Mode
The keyboard module remains active in stop mode. Clearing the
IMASKK bit in the keyboard status and control register enables keyboard
interrupt requests to bring the MCU out of stop mode.
Technical Data
232
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Keyboard Interrupt Module (KBI)
Freescale Semiconductor