Sharp PC-1500 Service Manual page 10

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(20) NMI
Non·maskable interrupt. A high NMI signal denotes an interrupt request, to which the MPU
responds unconditionally and the control mows to start the interrupt
pro~ssing
rout. i nc after
the contents of the memory address FFFC is moved into the high order byte of the program
counter and
the contents of the memory
address FFFD into the low order byte of the program
counter.
(21)
Ml
Maskable interrupt. A high on this signal makes interrupt request when interrupt enable is set.
The MPU responds uncond. i t ionally to this request. Control moves to start the Interrupt
pr~ssing
routine after the contents of the memory address FFF8 is mo,·ed into the high order
byte of the program counter, the contents of the memory address FF F9 are moved into the low
order byte of the program counter.
(221 OD
011tp11t diS<lble. When the OD
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