R01UH0822EJ0100 Rev.1.00
Page 135 of 1041
Jul 31, 2019
RX13T Group
9. Clock Generation Circuit
9.2.4
PLL Control Register 2 (PLLCR2)
Note:
Set the PRCR.PRC0 bit to 1 (write enabled) before rewriting this register.
This bit runs or stops the PLL circuit.
After setting the PLLEN bit to 0 (PLL is operating), confirm that the OSCOVFSR.PLOVF bit is 1 before switching the
system clock to the PLL clock.
That is, a fixed time for stabilization is required after the setting for PLL operation. A fixed time is also required for
oscillation to stop after the setting to stop PLL operation. Accordingly, take note of the following limitations when
starting and stopping PLL operation.
After stopping the PLL, confirm that the OSCOVFSR.PLOVF bit is 0 before restarting the PLL.
Confirm that the PLL is operating and that the OSCOVFSR.PLOVF bit is 1 before stopping the PLL.
Regardless of whether or not it is selected as the system clock, confirm that the OSCOVFSR.PLOVF bit is 1 before
executing a WAIT instruction to place the MCU in software standby mode.
After stopping the PLL, confirm that the OSCOVFSR.PLOVF bit is 0 and execute a WAIT instruction before
entering software standby mode.
When the PLL clock is selected by the SCKCR3.CKSEL[2:0] bits, do not set the PLLEN bit (PLL is stopped) to 1.
Address(es): 0008 002Ah
b7
b6
b5
b4
b3
b2
b1
b0
—
—
—
—
—
—
—
PLLEN
Value after reset:
0
0
0
0
0
0
0
1
Bit
Symbol
Bit Name
Description
R/W
b0
PLL Stop Control
0: PLL is operating.
1: PLL is stopped.
R/W
b7 to b1
—
Reserved
These bits are read as 0. The write value should be 0.
R/W