MC68HC901 Datasheet, PDF (23/73 Pages) Motorola, Inc – Multi-Function Peripheral

Bus Operation
I/O lines are placed in the high-impedance input mode, and the timer outputs are driven low.
External MFP signals are negated. Since the vector register (VR) is initialized to a $00, an
uninitialized MFP may not respond to an interrupt acknowledge cycle with the uninitialized
interrupt vector, $0F. Refer to Section 4.1.2 Interrupt Vector Number for more information.
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MC68HC901 USER’S MANUAL
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