
HD404849 Series
32
Standby
Oscillator: Active
Peripheral clocks: Active
All other clocks: Stop
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Yes
(SBY
only)
Watch
Oscillator: Stop
Suboscillator: Active
Peripheral clocks: Stop
All other clocks: Stop
Restart
processor clocks
Reset MCU
Execute
next instruction
Accept interrupt
Restart
processor clocks
No
Yes
IF = 1,
IM = 0, and
IE = 1
IF0
IM0
= 1
IF1
IM1
= 1
IFT= 1
IMTA
IFTB
IMTB
= 1
IM2
IF + IF3
IMTC
IM3
= 1
IMTD
= 1
No
Yes
IMIFAD
= 1
No
Stop
Oscillator: Stop
Suboscillator: Active/Stop
Peripheral clocks: Stop
All other clocks: Stop
RESET
= 0
STOPC
= 0
RAME = 1
RAME = 0
Yes
Yes
No
No
Execute
next instruction
(SBY
only)
(SBY
only)
(SBY
only)
(SBY
only)
RESET
= 0
Figure 15 MCU Operation Flowchart
Stop Mode:
In stop mode, all MCU operations stop and RAM data is retained. Therefore, the power
dissipation in this mode is the least of all modes. The OSC
1
and OSC
2
oscillator stops. The X1 and X2
oscillator can be selected to operate by setting bit 3 of the system clock select register (SSR: $029;
operating: SSR3 = 0, stop: SSR3 = 1) (figure 26). The MCU enters stop mode if the STOP instruction is
executed in active mode when bit 3 of timer mode register A (TMA: $008) is set to 0 (TMA3 = 0) (figure
41).
Stop mode is terminated by a
RESET
input or a
STOPC
input as shown in figure 16.
RESET
or
STOPC
must be applied for at least one t
RC
to stabilize oscillation (refer to the AC Characteristics section). When
the MCU restarts after stop mode is cancelled, all RAM contents before entering stop mode are retained,