Low-Power Consumption Modes; Table 3-2 Low-Power Consumption Mode At Each Clock Mode - Fujitsu MB89140 Series Hardware Manual

3.4 LOW-POWER CONSUMPTION MODES

The MB89140 series of microcontrollers have three standby modes: sleep, stop, and watch to reduce the
power consumption. Writing to the standby control register (STBC) switches to these three standby modes.
See 2.2 for setting and releasing each mode.
The MB89140 series of microcontrollers have a double clock module, and the low-power consumption modes
vary with the main clock and subclock modes. Whether or not an oscillation stabilization period is required at
release from each low-power consumption mode depends on the mask option of the power-on reset (see the
status transition chart in 2.2).
If the single clock module is specified with the mask option, the MB89140 series of microcontrollers can be
used as single clocks. If the microcontrollers are used as single clocks without specifying the single clock
module with the mask option, once the subclock mode is entered, it cannot be released. Therefore, when
using these controllers as a single clock, specify the single clock module with the mask option.

Table 3-2 Low-power Consumption Mode at Each Clock Mode

Function
Main clock
Subclock
Instruction
CPU ROM
RAM
I/O
Watch prescaler
Time-based timer
8-bit PWM
8/16-bit timer
Re-
12-bit MPG
source
8-bit SIO
10-bit A/D converter
External interrupt
Buzzer output
Watchdog timer
Notes:
A The operating speed is affected by the clock mode (main clock or subclock) and the gear function.
B The operating speed is not affected by the clock mode (main clock or subclock) and the gear function.
*1 The watch prescaler performs counting but no timer interrupt occurs.
*2 Although operation is possible, do not use this.
*3 When clock source used as watch prescaler
OPERATION
Main mode
Note
RUN SLEEP
— Operate Operate
— Operate Operate
A Operate Stop
A
Operate Hold
A
A Operate Hold
B Operate Operate
B Operate Operate
A Operate Operate
A Operate Operate
A Operate Operate
A Operate Operate
A Operate Operate
A Operate Operate
B Operate Operate
B Operate Stop
3-8
Sub-mode
STOP RUN SLEEP
Stop Stop Stop
Operate Operate Operate
Stop Operate Stop
Hold Operate Hold
Hold Operate Hold
1
Operate* Operate Operate
Stop Stop Stop
Stop Operate Operate
Stop Operate Operate
Stop Operate Operate
Stop Operate Operate
2
Operate Operate* Operate*
Operate Operate Operate
Stop Stop Stop
3
Stop Operate* Stop
STOP Watch
Stop Stop
Stop Operate
Stop Stop
Hold Hold
Hold Hold
Stop Operate
Stop Stop
Stop Stop
Stop Stop
Stop Stop
Stop Stop
2
Operate Operate
Operate Operate
Stop Stop
Stop Stop