
W O R K I N G W I T H T H E C P U
MemoryManagement Unit (MMU)
106
Hardware Reference NS9215
Invalidate entire TLB using R8: TLB Operations register (see “R8:TLB
Operations register” on page 97).
Invalidate TLB entry selected by MVA, using R8: TLB Operations register (see
“R8:TLB Operations register” on page 97).
Lockdown of TLB entries using R10: TLB Lockdown register (see “R10:TLB
Lockdown register” on page 101).
Access
permissions and
domains
For large and small pages, access permissions are defined for each subpage (1 KB for
small pages, 16 KB for large pages). Sections and tiny pages have a single set of
access permissions.
All regions of memory have an associated domain. A domain is the primary access
control mechanism for a region of memory. It defines the conditions necessary for
an access to proceed. The domain determines whether:
Access permissions are used to qualify the access.
The access is unconditionally allowed to proceed.
The access is unconditionally aborted.
In the latter two cases, the access permission attributes are ignored.
There are 16 domains, which are configured using R3: Domain Access Control
register (see “R3:Domain Access Control register” on page 91).
Translated entries
The TLB caches translated entries. During CPU memory accesses, the TLB provides
the protection information to the access control logic.
When the TLB contains a translated entry for the modified virtual address (MVA),
the access control logic determines whether:
Access is permitted and an off-chip access is required — the MMU outputs the
appropriate physical address corresponding to the MVA.
Access is permitted and an off-chip access is not required — the cache services
the access.
Access is not permitted — the MMU signals the CPU core to abort.
If the TLB misses (it does not contain an entry for the MVA), the translation table
walk hardware is invoked to retrieve the translation information from a translation
table in physical memory. When retrieved, the translation information is written
into the TLB, possible overwriting an existing value.
At reset, the MMU is turned off, no address mapping occurs, and all regions are
marked as noncachable and nonbufferable.
Содержание NS9215
Страница 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Страница 3: ......
Страница 4: ......
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...