11 CACHE CONTROLLER (CCU)
11-10
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
WBEMPTY is set to 0 by writing data to the write buffer and is set to 1 when the buffered data is read
out for writing to the external memory. The write buffer improves writing speed as the CPU does not
need to wait for completion of writing to the external memory. However, read the above flags to check
if the data has been written to, especially when data is written to a low-speed external device.
D[7:0]
Reserved
CCLK Division Ratio Select Register (CCU_CCLKDV)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
CCLK Division
Ratio Select
Register
(CCU_
CCLKDV)
0x302360
(32 bits)
D31–2 –
reserved
–
–
–
0 when being read.
D1–0 CLK_
DOWN[1:0]
CCLK division ratio select
CLK_DOWN[1:0] Division ratio
0x0 R/W Source clock: MCLK
0x3
0x2
0x1
0x0
1/8
1/4
1/2
1/1
D[31:2] Reserved
D[1:0]
CLK_DOWN[1:0]: CCLK Division Ratio Select Bits
Selects the division ratio to set the CCLK clock speed for operating the C33 PE Core and CCU. To re-
duce current consumption, operate the C33 PE Core and CCU using the slowest possible clock speed.
7.4 CCLK Division Ratio Selection
Table 11.
CLK_DOWN[1:0]
Division ratio
0x3
1/8
0x2
1/4
0x1
1/2
0x0
1/1
(Default: 0x0)
For more information on CCLK, see the “Clock Management Unit (CMU)” chapter.