NEC PD78F9488 - Manual (Page 310)

CHAPTER 17 STANDBY FUNCTION
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User’s Manual U15331EJ4V1UD
(2) Releasing HALT mode
The HALT mode can be released by the following three sources.
(a) Release by unmasked interrupt request
The HALT mode is released by an unmasked interrupt request. In this case, if interrupts are enabled to
be acknowledged, vectored interrupt servicing is performed. If interrupts are disabled, the instruction at
the next address is executed.
Figure 17-2. Releasing HALT Mode by Interrupt
HALT
instruction
Standby
release signal
Wait
Wait HALT mode
Operation
mode
Operation mode
Clock
Oscillation
Remarks 1. The broken lines indicate the case where the interrupt request that released the standby mode is
acknowledged.
2. The wait time is as follows:
• When vectored interrupt servicing is performed: 9 to 10 clocks
• When vectored interrupt servicing is not performed: 1 to 2 clocks
(b) Release by non-maskable interrupt request
The HALT mode is released regardless of whether interrupts are enabled or disabled, and vectored
interrupt servicing is performed.