Cypress S6J3200 Series, Manual

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CHAPTER 31:Memory Protection Unit for AXI
1136 S6J3200 Series Hardware Manual Document Number: 002-04852 Rev. *G
1.
Overview
This section describes the features of the MPU AXI.
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Features of the MPU AXI
The MPU AXI module monitors the accesses from AXI masters and checks each access against an
authorized set of access permissions. Access permissions ("permission attributes" here onwards) are
defined by "access permissions" bits. These bits are explained in Section "MPU access permissions".
MPU AXI provides eight regions and one background region. Each region has corresponding access
permission bits that defines the permission attributes for that particular region. Any unauthorized access
to memory space is flagged using Non-Maskable Interrupt. MPU AXI also collects information about the
unauthorized bus access and stores it in its internal registers.
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Each of the eight regions in MPU AXI is specified using corresponding start address and end
address
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Background region covers entire 4 GB address space
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On unauthorized access MPU AXI generates an NMI to the CPU
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MPU AXI collects information about the AXI master bus access that caused unauthorized access
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Supports 8-bit, 16-bit, and 32-bit bus accesses for configuration of registers in MPU AXI
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Supports lock, unlock feature for protection of registers from illegal write accesses
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Modification of registers in MPU AXI is only allowed in privileged mode
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Supports MPU stop feature that allows blocking of all the accesses to memory space
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Optionally supports privileged mode overwrite feature that allows overwrite of privilege attribute of
memory side AXI interface