NEC mPD789026 Subseries, User Manual

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CHAPTER 11 STANDBY FUNCTION
User's Manual U11919EJ3V0UM00
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(2) Releasing HALT mode
The HALT mode can be released by the following three types of sources:
(a) Releasing by unmasked interrupt request
The HALT mode is released by an unmasked interrupt request. In this case, if the interrupt request is
enabled to be accepted, vectored interrupt processing is performed. If the interrupt is disabled, the
instruction at the next address is executed.
Figure 11-2. Releasing HALT Mode by Interrupt
HALT
Instruction
Standby
Release Signal
Wait
Wait HALT Mode
Operation
Mode
Operation Mode
Clock
Oscillation
Remarks 1. The broken line indicates the case where the interrupt request that has released the
standby mode is accepted.
2. The wait time is as follows:
•
When vectored interrupt processing is performed : 9 to 10 clocks
•
When vectored interrupt processing is not performed : 1 to 2 clocks
(b) Releasing by non-maskable interrupt request
The HALT mode is released regardless of whether the interrupt is enabled or disabled, and vectored
interrupt processing is performed.