CHAPTER 15 STANDBY FUNCTION
(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 is enabled
to be acknowledged, vectored interrupt processing is performed. If the interrupt is disabled, the
instruction at the next address is executed.
Figure 15-2. Releasing HALT Mode by Interrupt
HALT
instruction
Wait
Standby
release signal
Operation
mode
HALT mode
Wait
Operation mode
Oscillation
Clock
Remarks 1. The broken line indicates the case where the interrupt request that has released the standby mode
is acknowledged.
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.
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User’s Manual U15075EJ1V0UM00
NEC [ NEC ]
