W78E054D Datasheet, PDF (48/89 Pages) List of Unclassifed Manufacturers – 8-bit microcontroller

W78E054D/W78E052D Data Sheet
interrupt is in service) occurs if the device is performing a write to IE, IP, IPH and then executes a
MUL or DIV instruction.
13.4 Interrupt Inputs
Since the external interrupt pins are sampled once each machine cycle, an input high or low should
hold for at least one machine cycle to ensure proper sampling. If the external interrupt is high for at
least one machine cycle, and then hold it low for at least one machine cycle. This is to ensure that the
transition is seen and that interrupt request flag IEn is set. IEn is automatically cleared by the CPU
when the service routine is called.
If the external interrupt is level-activated, the external source must hold the request active until the
requested interrupt is actually generated. If the external interrupt is still asserted when the interrupt
service routine is completed another interrupt will be generated. It is not necessary to clear the inter-
rupt flag IEn when the interrupt is level sensitive, it simply tracks the input pin level.
If an external interrupt is enabled when the W78E054D/W78E052D is put into Power Down or Idle
mode, the interrupt will cause the processor to wake up and resume operation. Refer to the section on
Power Reduction Modes for details.
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Publication Release Date: Jun 9, 2015
Revision A13