R01UH0040EJ0100 Rev.1.00
Page 235 of 1657
Sep 8, 2011
RX630 Group
9. Clock Generation Circuit
Note 3. When operation of the external bus clock is selected, the P53 I/O port pin function is not available because it is multiplexed on
the same pin as the BCLK pin function.
Note 4. When the SCKCR3.CKSEL[2:0] bits are selecting the sub-clock oscillator in low-speed operating mode 2, division by one is the
only frequency division setting allowed for the ICLK and FCLK.
SCKCR should not be modified in the following cases:
The operating power control mode transition status flag in the operating power control register
(OPCCR.OPCMTSF) is 1 (a transition to operating power control mode in progress)
The ROM P/E mode entry bit i in the flash P/E mode entry register (FENTRYR.FENTRYi) is 1 (ROM P/E mode) (i
= 0 to 3)
Time period from WAIT instruction issuance for a transition to sleep mode, to return from sleep mode to normal
operating mode
9.2.2
System Clock Control Register 2 (SCKCR2)
SCKCR2 should not be modified in the following cases:
The operating power control mode transition status flag in the operating power control register
(OPCCR.OPCMTSF) is 1 (a transition to operating power control mode in progress)
The ROM P/E mode entry bit i in the flash P/E mode entry register (FENTRYR.FENTRYi) is 1 (ROM P/E mode) (i
= 0 to 3)
Time period from WAIT instruction issuance for a transition to sleep mode, to return from sleep mode to normal
operating mode
UCK[3:0] Bits (USB Clock (UCLK) Select)
These bits select the frequency of the USB clock (UCLK).
The duty ratio is 2:1 when x1/3 is selected.
Address(es): 0008 0024h
b15
b14
b13
b12
b11
b10
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
——————
——
UCK[3:0]
IEBCK[3:0]
Value after reset:
00000
0000001
0001
Bit
Symbol
Bit Name
Description
R/W
b3 to b0
IEBCK[3:0]
IEBUS Clock (IECLK)
Select
b3
b0
0 0 0 1: ×1/2
0 0 1 0: ×1/4
0 0 1 1: ×1/8
0 1 0 0: ×1/16
0 1 0 1: ×1/32
0 1 1 0: ×1/64
1 1 0 0: ×1/6
Settings other than above are prohibited.
R/W
b7 to b4
UCK[3:0]
USB Clock (UCLK) Select
b7
b4
0 0 1 0: ×1/3
0 0 1 1: ×1/4
Settings other than above are prohibited when USB is in use. When
USB is not in use, these bits are read as 0. The write value should be
0.
R/W
b15 to b8
—
Reserved
These bits are read as 0. The write value should be 0.
R/W