Memory Protection Unit (MPU)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
17-2
Freescale Semiconductor
Preliminary
Figure 17-1. MPU Connections to AXBS-lite
17.1.2
Features
The MPU has these major features:
•
Support for 16 memory region descriptors, each 128 bits in size
— Specification of start and end addresses provide granularity for region sizes from 32 bytes to
4 GB
— MPU is invalid at reset, thus no access restrictions are enforced
— Two types of access control definitions: two processor core bus masters (e200z1 and e200z0)
support the traditional {read, write, execute} permissions with independent definitions for
supervisor and user mode accesses; the remaining three non-core bus masters (DMA, FlexRay,
and EBI) support {read, write} attributes
— Automatic hardware maintenance of the region descriptor valid bit removes issues associated
with maintaining a coherent image of the descriptor
— Alternate memory view of the access control word for each descriptor provides an efficient
mechanism to dynamically alter the access rights of a descriptor only
AXBS-lite
1 to 3
SRAM
EBI
AIPS
Flash Port 1
Z1 Inst
2
FlexRay
Z0
DMA
Z1 Data
EBI
1
Flash Port 0
splitter
MPU
Master ID 0
Master ID 2
Master ID 3
Master ID 4
Master ID 0
Master ID 1
m0
m2
m5
m1
m4
m3
mpu0
mpu1
mpu2
1 to 2
splitter
s3
s0
1
For factory test only.
2
For Z1, all instruction accesses to flash go through port P0. The path from the Z1 Instruction bus through
the 1 to 2 splitter and AXBS port m0 is only used for non-Flash (i.e. RAM and BAM) instruction fetches.