NEC switch - Manual (Page 181)

CHAPTER 12 STANDBY FUNCTION
User’s Manual U12978EJ3V0UD
181
(2) Releasing HALT mode
The HALT mode can be released by the following three sources.
(a) Releasing 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 12-2. 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 has 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) Releasing by non-maskable interrupt request
The HALT mode is released regardless of whether interrupts are enabled or disabled, and vectored
interrupt servicing is performed.