SH7641 Datasheet, PDF (232/1036 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family / SH7641 Series

Section 7 Cache
7.2 Register Descriptions
The cache has the following registers.
• Cache control register 1 (CCR1)
• Cache control register 2 (CCR2)
7.2.1 Cache Control Register 1 (CCR1)
The cache is enabled or disabled using the CE bit in CCR1. CCR1 also has the CF bit (which
invalidates all cache entries), and the WT and WB bits (which select either write-through mode or
write-back mode). Programs that change the contents of CCR1 should be placed in an address
space that is not cached. When updating the contents of CCR1, bits 31 to 4 must always be cleared
to 0.
CCR1 is initialized to H'00000000 by a power-on or manual reset and retain the previous value by
standby mode, module standby mode, and sleep mode.
Bit
31 to 4
Bit Name

3
CF
2
WB
1
WT
Initial
Value
All 0
0
0
0
R/W Description
R
Reserved
These bits are always read as 0. The write value
should always be 0.
R/W Cache Flush
Writing 1 flushes all cache entries (clears the V, U,
and LRU bits of all cache entries to 0). Always reads
0. Write-back to external memory is not performed
when the cache is flushed.
R/W Write Back
Switches write-back/write-through the cache's
operating mode for area P1.
0: Write-through mode
1: Write-back mode
R/W Write Through
Indicates the cache's operating mode for areas P0 and
P3.
0: Write-back mode
1: Write-through mode
Rev. 4.00 Sep. 14, 2005 Page 182 of 982
REJ09B0023-0400