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CHAPTER 3 CPU
Table 3.7-2 Standby Control Register (STBC) Bits
Bit
Function
Bit 7
STP:
Stop bit
Sets the CPU changing to stop mode.
Writing "1" to this bit sets the CPU changing to stop mode.
Writing "0" to this bit has no effect on operation.
Reading this bit always returns "0".
Bit 6
SLP:
Sleep bit
Sets the CPU changing to sleep mode.
Writing "1" to this bit sets the CPU changing to sleep mode.
Writing "0" to this bit has no effect on operation.
Reading this bit always returns "0".
Bit 5
SPL:
Pin state
specification
bit
Specifies the states of the external pins during stop mode
and watch mode.
Writing "0" to this bit specifies that external pin hold their
states (levels) on changing to stop mode or watch mode.
Writing "1" to this bit specifies that external pins to go to high
impedance state on entering stop mode or watch mode. (Pin
with a pull-up resistor (optional) go to "H" level.)
Initialized to "0" by a reset.
Bit 4
RST:
Software reset
bit
Specifies a software reset.
Writing "0" to this bit generates an internal reset source for
four instruction cycles.
Writing "1" to this bit has no effect on operation.
Reading this bit always returns "1".
Note:
When the software reset is applied in subclock mode,
operation will start up in main clock mode after an oscillation
stabilization delay time. For this reason, if the reset output
option is selected, the RST signal will be output during the
oscillation stabilization delay time.
Bit 3
TMD: Watch
bit
Sets the CPU changing to watch mode.
A write to this bit is valid only in subclock mode (SYCC: SCS
= 0).
Writing "1" to this bit sets the CPU changing to watch mode.
Writing "0" to this bit has no effect on operation.
Reading this bit always returns "0".
Bit 2
Bit 1
Bit 0
Unused bits
The read value is indeterminate.
Writing to these bits has no effect on operation.