Datasheet

CHAPTER 11 STANDBY FUNCTION
User’s Manual U18172EJ3V0UD
192
11.2.2 STOP mode
(1) STOP mode setting and operating statuses
The STOP mode is set by executing the STOP instruction.
Caution Because an interrupt request signal is used to clear the standby mode, if there is an interrupt
source with the interrupt request flag set and the interrupt mask flag reset, the standby
mode is immediately cleared if set. Thus, in the STOP mode, the normal operation mode is
restored after the STOP instruction is executed and then the operation is stopped for the
duration of 34
μ s (TYP.) (after an additional wait time for stabilizing oscillation set by the
oscillation stabilization time select register (OSTS) has elapsed when crystal/ceramic
oscillation is used).
The operating statuses in the STOP mode are shown below.
Table 11-4. Operating Statuses in STOP Mode
Low-Speed Internal Oscillator can be stopped
Note 1
.
Setting of STOP Mode
Item
Low-Speed Internal
Oscillator cannot be
stopped
Note 1
.
When Low-Speed Internal
Oscillation Continues
When Low-Speed Internal
Oscillation Stops
System clock Oscillation stops.
CPU Operation stops.
Port (latch) Holds status before STOP mode was set.
16-bit timer/event counter 00
Note 2
Operation stops.
Sets count clock to fXP to fXP/2
12
Operation stops.
8-bit timer
H1
Sets count clock to f
RL/2
7
Operable Operable Operation stops.
“System clock” selected as
operating clock
Setting disabled. Operation stops.
Watchdog
timer
“Low-speed internal oscillation
clock” selected as operating
clock
Operable
(Operation continues)
Operation stops.
A/D converter
Note 2
Operation stops.
Power-on-clear circuit Always operates.
Low-voltage detector Operable
External interrupt Operable
Notes 1. “Cannot be stopped” or “Stopped by software” is selected for low-speed internal oscillator by the option byte
(for the option byte, see CHAPTER 15 OPTION BYTE).
2.
μ PD78F920x only
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