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Section 7 Cache
Rev. 4.00 Sep. 14, 2005 Page 183 of 982
REJ09B0023-0400
Bit Bit
Name
Initial
Value R/W Description
0 CE 0 R/W
Cache
Enable
Indicates whether the cache function is used.
0: Cache not used
1: Cache used
7.2.2
Cache Control Register 2 (CCR2)
CCR2 is used to enable or disable the cache locking function and is valid in cache locking mode
only. In cache locking mode, the DSP bit (bit 12) in the status register (SR) of the CPU is set to 1.
Alternatively, the lock enable bit (bit 16) in CCR2 is set to 1. In the non-cache-locking mode, the
cache locking function is invalid.
When a cache miss occurs in cache locking mode by executing the prefetch instruction (PREF
@Rn), the line of data pointed to by Rn is loaded into the cache according to bits 9 and 8 (the
W3LOAD and W3LOCK bits) and bits 1 and 0 (the W2LOAD and W2LOCK bits) in CCR2. The
relationship between the setting of each bit and a way, to be replaced when the prefetch instruction
is executed, are listed in table 7.4. On the other hand, when the prefetch instruction is executed
and a cache hit occurs, new data is not fetched and the entry which is already enabled is held. For
example, when the prefetch instruction is executed with W3LOAD = 1 and W3LOCK = 1
specified in cache locking mode while one-line data already exists in way 0 which is specified by
Rn, a cache hit occurs and data is not fetched to way 3.
In the cache access other than the prefetch instruction in cache locking mode, ways to be replaced
by bits W3LOCK and W2LOCK are restricted. The relationship between the setting of each bit in
CCR2 and ways to be replaced are listed in table 7.5.
The program that change the contents of CCR2 should be placed in an address space that is not
cached.
CCR2 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.
Summary of Contents for HD6417641
Page 2: ...Rev 4 00 Sep 14 2005 Page ii of l...
Page 7: ...Rev 4 00 Sep 14 2005 Page vii of l...
Page 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
Page 12: ...Rev 4 00 Sep 14 2005 Page xii of l...
Page 28: ...Rev 4 00 Sep 14 2005 Page xxviii of l...
Page 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Page 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Page 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Page 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Page 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Page 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Page 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Page 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Page 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Page 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Page 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Page 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Page 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
Page 1032: ...Rev 4 00 Sep 14 2005 Page 982 of 982 REJ09B0023 0400 X X Y data addressing 52 X Y memory 193...
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