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CHAPTER 16 STANDBY FUNCTION
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16.2.2 STOP mode
(1)
Setting and operation status of STOP mode
STOP mode is set by executing the STOP instruction.
Cautions 1. When STOP mode is set, the X2 pin is internally pulled up to V
DD
to suppress the
current leakage of the oscillation circuit block. Therefore, do not use STOP mode in a
system where the external clock is used as the system clock.
2. Because standby mode can be released by an interrupt request signal, 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 STOP mode is set, therefore, HALT
mode is set immediately after the STOP instruction has been executed, the wait time
set by the oscillation settling time selection register (OSTS) elapses, and then
operation mode is set.
The operation status in STOP mode is shown in the following table.
Table 16-3. Operation Statuses in STOP Mode
STOP Mode Operation Status While the Main System Clock is Running
Item
While the Subsystem Clock is Running
While the Subsystem Clock is Not Running
Clock generation circuit
Main system clock oscillation stopped
CPU
Operation disabled
Port (output latch)
Remains in the state existing before the selection of STOP mode
16-bit timer counter (TM90)
Operation enabled
Note 1
Operation disabled
8-bit timer/event counter (TM80)
Operation enabled
Note 2
8-bit timer/event counter (TM81)
Operation enabled
Note 3
8-bit timer counter (TM82)
Operation enabled
Note 1
Operation disabled
Watch timer
Operation enabled
Note 1
Operation disabled
Watchdog timer
Operation disabled
Serial interface
Operation enabled
Note 4
SMB
Operation enabled
Note 5
A/D converter
Operation disabled
Multiplier
Operation disabled
External interrupt
Operation enabled
Note 6
Notes 1.
Operation is enabled while the subsystem clock is selected.
2.
Operation is enabled only when TI80 is selected as the count clock.
3.
Operation is enabled only when TI81 is selected as the count clock.
4.
Operation is enabled in both 3-wire serial I/O and UART modes while an external clock is being
used.
5.
While in slave mode, an interrupt can be generated when an address match is found.
6.
Maskable interrupt that is not masked