Datasheet

Table Of Contents
Section 6 Power-Down Modes
Rev. 2.00 Jul. 04, 2007 Page 105 of 692
REJ09B0309-0200
6.1.3 System Control Register 3 (SYSCR3)
SYSCR3 controls the power-down modes with SYSCR1 and SYSCR2.
Bit Bit Name
Initial
Value
R/W Description
7 to 1 All 1
Reserved
These bits are always read as 1 and cannot be
modified.
0 STS3 0 R/W
Standby Timer Select 3
Specifies the time the CPU and peripheral modules wait
for stable clock operation after exiting from standby
mode, subactive mode, or watch mode to active mode
or sleep mode. This bit should be specified together
with the STS2 to STS0 bits in SYSCR1 according to the
operating frequency so that the wait time is at least
equal to the oscillation stabilization time. The
relationship between the specified value and the
number of wait states is shown in table 6.1.
When an external clock is to be used, the minimum
value (STS3 = 0, STS2 = 1, STS1 = 0, STS0 = 1) is
recommended. When the on-chip oscillator for the
system clock is to be used, four states (STS3 = 1, STS2
= 1, STS1 = 0, STS0 = 1) is recommended. If a setting
other than the recommended value is made, operation
may start before the end of the wait time.