Difference between revisions of "embOS MPU on CortexM"
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− | These bits are implemented in the Cortex-M MPU Region Base Attribute and Size Register (0xE000EDA0): |
+ | These bits are implemented in the Cortex-M MPU Region Base Attribute and Size Register (0xE000EDA0): |
− | 31:29 Reserved |
+ | 31:29 Reserved |
− | 28 XN R/W — Instruction Access Disable (1 = disable instruction fetch from this region; an attempt to do so will result in a memory management fault) |
+ | 28 XN R/W — Instruction Access Disable (1 = disable instruction fetch from this region; an attempt to do so will result in a memory management fault) |
− | 27 Reserved |
+ | 27 Reserved |
− | 26:24 AP R/W — Data Access Permission field |
+ | 26:24 AP R/W — Data Access Permission field |
− | 23:22 Reserved |
+ | 23:22 Reserved |
− | 21:19 TEX R/W — Type Extension field |
+ | 21:19 TEX R/W — Type Extension field |
− | 18 S R/W — Shareable |
+ | 18 S R/W — Shareable |
− | 17 C R/W — Cacheable |
+ | 17 C R/W — Cacheable |
− | 16 B R/W — Bufferable |
+ | 16 B R/W — Bufferable |
− | 15:8 SRD R/W — Subregion disable |
+ | 15:8 SRD R/W — Subregion disable |
− | 7:6 Reserved |
+ | 7:6 Reserved |
− | 5:1 REGION SIZE R/W — MPU Protection Region size |
+ | 5:1 REGION SIZE R/W — MPU Protection Region size |
− | 0 ENABLE R/W — Region enable |
+ | 0 ENABLE R/W — Region enable |
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Revision as of 17:28, 13 May 2019
embOS is a priority-controlled real-time operating system, designed to be used as foundation for the development of embedded applications.
FAQ
I want use the Cortex-M memory attributes with embOS-MPU Cortex-M
The Cortex-M memory attributes include the following:
Bufferable: Write to memory can be carried out by a write buffer while the processor continues on next instruction execution.
Cacheable: Data obtained from memory read can be copied to a memory cache so that next time it is accessed the value can be obtained from the cache to speed up the program execution.
Sharable: Data in this memory region could be shared by multiple bus masters. Memory system needs to ensure coherency of data between different bus masters in shareable memory region.
TEX: Type Extension field
These bits are implemented in the Cortex-M MPU Region Base Attribute and Size Register (0xE000EDA0): 31:29 Reserved 28 XN R/W — Instruction Access Disable (1 = disable instruction fetch from this region; an attempt to do so will result in a memory management fault) 27 Reserved 26:24 AP R/W — Data Access Permission field 23:22 Reserved 21:19 TEX R/W — Type Extension field 18 S R/W — Shareable 17 C R/W — Cacheable 16 B R/W — Bufferable 15:8 SRD R/W — Subregion disable 7:6 Reserved 5:1 REGION SIZE R/W — MPU Protection Region size 0 ENABLE R/W — Region enable