11 CACHE CONTROLLER (CCU)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
11-9
D3
ICLKS: Instruction Cache Lock Status Bit
Indicates the lock status of the instruction cache. (Default: undefined)
1 (R):
Locked
0 (R):
Not locked
Read ICLKS to check whether the instruction cache is locked or not when the cache lock function is
enabled.
D2
DCLKS: Data Cache Lock Status Bit
Indicates the lock status of the data cache. (Default: undefined)
1 (R):
Locked
0 (R):
Not locked
Read DCLKS to check whether the data cache is locked or not when the cache lock function is enabled.
D1
ICS: Instruction Cache Operating Status Bit
Indicates the operating status of the instruction cache. (Default: undefined)
1 (R):
Active
0 (R):
Inactive
Setting IC/CCU_CFG register to 1 activates the instruction cache and sets ICS to 1. Setting IC to 0
flushes the instruction cache and disables caching. Note that the instruction cache is flushed several
cycles after writing 0 to IC. When flushing finishes, ICS is reset to 0. To resume caching after flushing,
check that flushing has completed by reading ICS.
D0
DCS: Data Cache Operating Status Bit
Indicates the operating status of the data cache. (Default: undefined)
1 (R):
Active
0 (R):
Inactive
Setting DC/CCU_CFG register to 1 activates the data cache and sets DCS to 1. Setting DC to 0 flushes
the data cache and disables caching. Note that the data cache is flushed several cycles after writing 0
to DC. When flushing finishes, DCS is reset to 0. To resume caching after flushing, check that flushing
has completed by reading DCS.
Cache Write Buffer Status Register (CCU_WB_STAT)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
Cache Write
Buffer Status
Register
(CCU_WB_
STAT)
0x302318
(32 bits)
D31–10 –
reserved
–
–
–
0 when being read.
D9
WEFINISH Write-finish flag
1 Finished
0 Writing
1
R
D8
WBEMPTY Write buffer empty flag
1 Empty
0 Full
1
R
D7–0 –
reserved
–
X
–
D[31:10] Reserved
D9
WEFINISH: Write-Finish Flag Bit
Indicates whether the data writing from the write buffer to the external memory has finished or not.
1 (R):
Finished (default)
0 (R):
During writing
When the write buffer is enabled, writing data to the external memory is performed in two steps, first
the data is written to the write buffer and then the external memory is updated. WEFINISH is set to 0
when data is loaded to the write buffer and is set to 1 upon completion of writing to the external memo-
ry.
D8
WBEMPTY: Write Buffer Empty Flag Bit
Indicates the write buffer status.
1 (R):
Empty (default)
0 (R):
Full