MC68HC08AZ0 Datasheet, PDF (324/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
Keyboard Module (KB)
If the MODEK bit is clear, the keyboard interrupt pin is
falling-edge-sensitive only. With MODEK clear, a vector fetch or
software clear immediately clears the keyboard interrupt latch.
Reset clears the keyboard interrupt latch and the MODEK bit, clearing
the interrupt request even if a keyboard interrupt pin stays at logic zero.
The keyboard flag bit (KEYF) in the keyboard status and control register
can be used to see if a pending interrupt exists. The KEYF bit is not
affected by the keyboard interrupt mask bit (IMASKK) which makes it
useful in applications where polling is preferred.
To determine the logic level on a keyboard interrupt pin, use the data
direction register to configure the pin as an input and read the data
register.
NOTE:
Setting a keyboard interrupt enable bit (KBxIE) forces the corresponding
keyboard interrupt pin to be an input, overriding the data direction
register. However, the data direction register bit must be a logic zero for
software to read the pin.
MC68HC08AZ0
322
Keyboard Module (KB)
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