Architecture
98
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Memory Protection Unit (MPU)
Table 5-3. Device Master Settings
Master
Privilege ID
Privilege Level
Access Type
EDMA3_0_CC0
Inherited
Inherited
DMA
EDMA3_0_TC0 and EDMA3_0_TC1
Inherited
Inherited
DMA
EDMA3_1_CC0
Inherited
Inherited
DMA
EDMA3_1_TC0
Inherited
Inherited
DMA
ARM (instruction access)
0
Software dependant
Instruction
ARM (data access)
0
Software dependant
Data
PRU0/PRU1
2
Supervisor
DMA
HPI
3
User
DMA
EMAC
4
Supervisor
Data/DMA
USB1.1
5
Supervisor
DMA
USB2.0
6
Supervisor
DMA
LCD Controller
7
Supervisor
DMA
uPP
8
Supervisor
DMA
SATA
9
Supervisor
DMA
VPIF DMA0
10
Supervisor
DMA
VPIF DMA1
11
Supervisor
DMA
5.2.2 Memory Protection Ranges
NOTE:
In some cases the amount of physical memory in actual use may be less than the maximum
amount of memory supported by the device. For example, the device may support a total of
512 Mbytes of SDRAM memory, but your design may only populate 128 Mbytes. In such
cases, the unpopulated memory range must be protected in order to prevent
unintended/disallowed aliased access to protected memory. One of the programmable
address ranges could be used to detect accesses to this unpopulated memory.
The MPU divides its assigned memory into address ranges. Each MPU can support one fixed address
range and multiple programmable address ranges. The fixed address range is configured to an exact
address. The programmable address range allows software to program the start and end addresses.
Each address range has the following set of registers:
•
Range start and end address registers (MPSAR and MPEAR): Specifies the starting and ending
address of the address range.
•
Memory protection page attribute register (MPPA): Use to program the permission settings of the
address range.
It is allowed to configure ranges such that they overlap each other. In this case, all the overlapped ranges
must allow the access, otherwise the access is not allowed. The final permissions given to the access are
the lowest of each type of permission from any hit range.
Addresses not covered by a range are either allowed or disallowed based on the configuration of the
MPU. The MPU can be configured for assumed allowed or assumed disallowed mode as dictated by the
ASSUME_ALLOWED bit in the configuration register (CONFIG).