R01UH0822EJ0100 Rev.1.00
Page 139 of 1041
Jul 31, 2019
RX13T Group
9. Clock Generation Circuit
9.2.8
High-Speed On-Chip Oscillator Control Register (HOCOCR)
Note:
Set the PRCR.PRC0 bit to 1 (write enabled) before rewriting this register.
Note 1. The HCSTP bit value after a reset is 0 when the HOCO oscillation enable bit in option function select register 1
(OFS1.HOCOEN) is 0. The HCSTP bit value after a reset is 1 when the OFS1.HOCOEN bit is 1.
Set the high-speed on-chip wait control register before setting this register.
This bit runs or stops the HOCO.
When changing the HCSTP bit from 1 to 0 (i.e. changing the HOCO clock from stopped to operating), confirm that the
OSCOVFSR.HCOVF flag is 1 before switching the system clock to the HOCO clock.
That is, a fixed time for stabilization of oscillation is required after the setting for HOCO 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.
After stopping the HOCO, confirm that the OSCOVFSR.HCOVF flag is 0 before restarting the HOCO.
Confirm that the HOCO is operating and that the OSCOVFSR.HCOVF flag is 1 before stopping the HOCO.
Regardless of whether or not it is selected as the system clock, confirm that the OSCOVFSR.HCOVF flag is 1
before executing a WAIT instruction to place the MCU in software standby mode.
After stopping the HOCO, confirm that the OSCOVFSR.HCOVF flag is 0 and execute a WAIT instruction before
entering software standby mode.
While the HOCO is selected by the SCKCR3.CKSEL[2:0] bits, do not set the HCSTP bit to 1 (HOCO is stopped).
Address(es): 0008 0036h
b7
b6
b5
b4
b3
b2
b1
b0
—
—
—
—
—
—
—
HCSTP
Value after reset:
0
0
0
0
0
0
0
0/1
Bit
Symbol
Bit Name
Description
R/W
b0
HOCO Stop
0: HOCO is operating.
1: HOCO is stopped.
R/W
b7 to b1
—
Reserved
These bits are read as 0. The write value should be 0.
R/W