MC81F4x16
27. POWER DOWN OPERATION
In the power-down modes, power consumption is reduced considerably. For applications where power
consumption is a critical factor, device provides two kinds of power saving functions, STOP mode and
SLEEP mode. Table 27-1 on page 100, shows the status of each Power Saving Mode. SLEEP mode
is entered by the SSCR register to “0Fh”. and STOP mode is entered by STOP instruction after the
SSCR register to “5Ah”.
Note:
** If you use 20pin package, you must set R12 port as an low OUTPUT mode even it is
not exist in 20pin package. **
In fact, R12 port is exist in side of the package and it‟s reset status is input mode. If it is in
input mode it course current leakage when the MCU falls in stop/sleep mode. So you must
set it as an output mode before fall in stop/sleep.
It is recommendable to set R12 port as an low OUTPUT mode at initial time.
You do not have to care about it if you use other packages.
27.1 Sleep Mode
In this mode, the internal oscillation circuits remain active. Oscillation continues and peripherals are
operated normally but CPU stops. Movement of all peripherals is shown in Table 27-1 on page 100.
SLEEP mode is entered by setting the SSCR register to “0Fh”. It is released by Reset or interrupt. To
be released by interrupt, interrupt should be enabled before SLEEP mode.
SSCR
STOP AND SLEEP CONTROL REGISTER
00F5H
7
6
5
4
3
2
1
0
SSCR
One byte register
Reset value: 00H
W
W
W
W
W
W
W
W
5Ah : STOP
0Fh : SLEEP
It is used to set the stop or sleep mode.
Note :
To get into STOP mode, SSCR must be set to 5AH just before STOP instruction execution.
At STOP mode, Stop & Sleep Control Register (SSCR) value is cleared automatically when
released.
To get into SLEEP mode, SSCR must be set to 0FH.
Release the SLEEP mode
172
October 19, 2009 Ver.1.35
FINECHIPS [ FINECHIPS ]
