Freescale Semiconductor, Inc.
Keyboard/External Interrupt Module (KBI)
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.
14.5 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-
consumption standby modes.
14.5.1 Wait Mode
The IRQ1/keyboard interrupts remain active in wait mode. Clearing the
IMASKI or IMASKK bits in the IRQ and keyboard status and control
register enables keyboard interrupt requests to bring the MCU out of wait
mode.
14.5.2 Stop Mode
The IRQ1/keyboard interrupt remains active in stop mode. Clearing the
IMASKI or IMASKK bit in the IRQ and keyboard status and control
register enables keyboard interrupt requests to bring the MCU out of
stop mode.
Advance Information
192
MC68HC908RFRK2
Keyboard/External Interrupt Module (KBI)
MOTOROLA
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