
. . . . .
W O R K I N G W I T H T H E C P U
Caches and write buffer
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129
ICache I and M
bit settings
This table gives the I and M bit settings for the ICache, and the associated behavior.
ICache page table
C bit settings
This table shows the page table C bit settings for the ICache (R1 I bit = M bit = 1).
R1 register C and
M bits for DCache
This table gives the R1: Control register C and M bit settings for DCache, and the
associated behavior.
DCache page
table C and B
settings
This table gives the page table C and B bit settings for the DCache (R1: Control
register C bit = M bit = 1), and the associated behavior.
R1 I bit
R1 M bit
ARM926EJ-S behavior
0
-----
ICache disabled. All instruction fetches are fetched from external memory
(AHB).
1
0
ICache enabled, MMU disabled. All instruction fetches are cachable, with no
protection checks. All addresses are flat-mapped; that is, VA=MVA=PA.
1
1
ICache enabled, MMU enabled. Instruction fetches are cachable or
noncachable, depending on the page descriptor C bit (see “ICache page table
C bit settings” on page 129), and protection checks are performed. All
addresses are remapped from VA to PA, depending on the page entry; that
is, the VA is translated to MVA and the MVA is remapped to a PA.
Page table C
bit
Description
ARM926EJ-S behavior
0
Noncachable
ICache disabled. All instruction fetches are fetched from external
memory.
1
Cachable
Cache hit
Read from the ICache.
Cache miss
Linefill from external memory.
R1 C bit
R1 M bit
ARM926EJ-S behavior
0
0
DCache disabled. All data accesses are to the external memory.
1
0
DCache enabled, MMU disabled. All data accesses are noncachable,
nonbufferable, with no protection checks. All addresses are flat-mapped; that
is, VA=MVA=PA.
1
1
DCache enabled, MMU enabled. All data accesses are cachable or
noncachable, depending on the page descriptor C bit and B bit (see “DCache
page table C and B settings” on page 129), and protection checks are
performed. All addresses are remapped from VA to PA, depending on the
MMU page table entry; that is, the VA is translated to an MVA and the MVA
is remapped to a PA.
Содержание NS9215
Страница 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
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Страница 26: ...26 Hardware Reference NS9215...
Страница 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Страница 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Страница 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Страница 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Страница 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Страница 260: ...M E MO R Y C O N T ROL L E R StaticMemory Turn Round Delay 0 3 registers 260 Hardware Reference NS9215...
Страница 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Страница 362: ...A E S D AT A E N C R Y P T I O N D E C R Y P T I O N M O D U L E CCM mode 362 Hardware Reference NS9215...
Страница 384: ...I O HU B M OD UL E Module Direct Mode TX Data Last FIFO 384 Hardware Reference NS9215 31 March 2008...
Страница 414: ...S E R I A L C ON T RO L M O D U L E U ART UART Modem Status register 414 Hardware Reference NS9215...
Страница 446: ...S E R I A L C ON T RO L M O D U L E S PI SPI timing characteristics 446 Hardware Reference NS9215...
Страница 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Страница 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Страница 514: ...PA CKA GING Processor Dimensions 514 Hardware Reference NS9215 P r o c e s s o r D i m e n s i o n s...
Страница 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Страница 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...