R01UH0823EJ0100 Rev.1.00
Page 181 of 1823
Jul 31, 2019
RX23W Group
9. Clock Generation Circuit
9.2.9
Low-Speed On-Chip Oscillator Control Register (LOCOCR)
Note:
Set the PRCR.PRC0 bit to 1 (write enabled) before rewriting this register.
This bit runs or stops the LOCO.
After the setting of the LCSTP bit has been changed so that the LOCO operates, only start using the LOCO clock after
the LOCO clock oscillation stabilization time (t
LOCO
) has elapsed.
That is, a fixed time for stabilization of oscillation is required after the setting for LOCO operation. A fixed time is also
required for oscillation to stop after the setting to stop the oscillator. Accordingly, take note of the following limitations
when starting and stopping the oscillator.
When restarting the LOCO after it has been stopped, allow at least five cycles of the LOCO as an interval over
which it is still stopped.
Ensure that oscillation by the LOCO is stable when making the setting to stop the LOCO.
Regardless of whether or not it is selected as the system clock, ensure that oscillation by the LOCO is stable before
executing a WAIT instruction to place the chip on software standby.
When a transition to software standby mode is to follow the setting to stop the LOCO, wait for at least three cycles
of the LOCO after the setting to stop the LOCO and before executing the WAIT instruction.
While the LOCO is selected by the SCKCR3.CKSEL[2:0] bits, do not set the LCSTP bit to 1 (LOCO is stopped).
While low-speed operating mode is selected by the SOPCCR.SOPCM bit, do not set the LCSTP bit to 0 (LOCO is
operating).
Address(es): 0008 0034h
b7
b6
b5
b4
b3
b2
b1
b0
—
—
—
—
—
—
—
LCSTP
Value after reset:
0
0
0
0
0
0
0
0
Bit
Symbol
Bit Name
Description
R/W
b0
LOCO Stop
0: LOCO is operating.
1: LOCO is stopped.
R/W
b7 to b1
—
Reserved
These bits are read as 0. The write value should be 0.
R/W