Stop Mode; Operation Statuses In Stop Mode - NEC PD789488 User Manual

17.2.2 STOP mode

(1) Setting and operation status of STOP mode
The STOP mode is set by executing the STOP instruction.
Caution Because the standby mode can be released by an interrupt request signal, the standby
mode is released as soon as it is set if there is an interrupt source whose interrupt request
flag is set and interrupt mask flag is reset. When the STOP mode is set, therefore, the
HALT mode is set immediately after the STOP instruction has been executed, the wait time
set by the oscillation stabilization time selection register (OSTS) elapses, and then the
operation mode is set.
The operation statuses in the STOP mode are shown in the following table.
Item
Main system clock Oscillation stopped
Subsystem clock ×4 Operation stopped
multiplication circuit
CPU Operation stopped
Ports (output latches) Status before STOP mode setting retained
16-bit timer 20 Operation stopped
8-bit timer 50 Operable
8-bit timer 60 Operable
8-bit timer 61 Operable
Watch timer Operable
Watchdog timer Operation stopped
Key return circuit Operable
Serial interface 20 Operable
Serial interface 1A0 Operable
LCD controller/driver Operable
A/D converter Operation stopped
Multiplier Operation stopped
Remote controller Operable
Note 6
receiver
External interrupts Operable
Notes 1. Operation is enabled when either the subsystem clock or the input signal from the timer 60 (when timer
60 is operable) is selected as the count clock.
2. Operation is enabled when the input signal from timer 60 (when timer 60 is operable) is selected as the
count clock.
3. Operation is enabled when the external input clock is selected as the count clock.
4. Operation is enabled when the subsystem clock is selected.
5. Operation is enabled only for a maskable interrupt that is not masked.
µ
6. PD789489 and 78F9489 only
7. Operation is enabled only for a maskable interrupt that is not masked.
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CHAPTER 17 STANDBY FUNCTION
Table 17-3. Operation Statuses in STOP Mode
STOP Mode Operation Status During Main System Clock Operation
Subsystem Clock Operating
Note 1
Note 3
Note 3
Note 4
Note 5
Note 5
Note 4
Note 4
Note 7
User's Manual U15331EJ4V1UD
Subsystem Clock Stopped
Note 2
Operable
Operation stopped
Operation stopped
Operation stopped