SH7211 Datasheet, PDF (96/1228 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family

Section 4 Clock Pulse Generator (CPG)
4.4.3 AD Clock Frequency Control Register (ACLKCR)
ACLKCR is an 8-bit readable/writable register that can be accessed only in byte units. ACLKCR
is only initialized to H'43 by a power-on reset, but retains its previous value by a manual reset or
in software standby mode.
Bit: 7
6
5
4
3
2
1
0
ASSCS[1:0]
-
-
-
-
ASDIVS[1:0]
Initial value: 0
1
0
0
0
0
1
1
R/W: R/W R/W R
R
R
R R/W R/W
Bit
7, 6
5 to 2
1, 0
Initial
Bit Name Value R/W Description
ASSCS[1:0] 01
R/W Source Clock Select
These bits select the source clock.
00: Clock stoppage
01: PLL1 output clock
10: Reserved (setting prohibited)
11: Reserved (setting prohibited)
⎯
All 0
R
Reserved
These bits are always read as 0. The write value
should always be 0.
ASDIVS[1:0] 11
R/W Division Ratio Select
These bits specify the frequency division ratio of the
source clock. Set these bits so that the output clock is
40 MHz or less, and also an integer multiple of the
peripheral clock frequency (Pφ).
00: × 1 time
01: × 1/2 time
10: Setting prohibited
11: × 1/4 time
Rev. 2.00 May. 08, 2008 Page 72 of 1200
REJ09B0344-0200