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Introduction
MPC5644A Microcontroller Reference Manual, Rev. 6
36
Freescale Semiconductor
•
Automatic pushing or popping of preempted priority to or from a LIFO
•
Ability to modify the ISR or task priority to implement the priority ceiling protocol for accessing
shared resources
•
Low latency—three clocks from receipt of interrupt request from peripheral to interrupt request to
processor
This device also includes a non-maskable interrupt (NMI) pin that bypasses the INTC and multiplexing
logic.
1.4.6
Memory protection unit (MPU)
The Memory Protection Unit (MPU) provides hardware access control for all memory references
generated in a device. Using preprogrammed region descriptors, which define memory spaces and their
associated access rights, the MPU concurrently monitors all system bus transactions and evaluates the
appropriateness of each transfer. Memory references with sufficient access control rights are allowed to
complete; references that are not mapped to any region descriptor or have insufficient rights are terminated
with a protection error response.
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: processor core bus master supports the traditional
{read, write, execute} permissions with independent definitions for supervisor and user mode
accesses; the remaining non-core bus masters (eDMA, FlexRay, and EBI
1
) 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
1
— For overlapping region descriptors, priority is given to permission granting over access
denying as this approach provides more flexibility to system software
•
Support for two XBAR slave port connections (SRAM and PBRIDGE)
— For each connected XBAR slave port (SRAM and PBRIDGE), MPU hardware monitors every
port access using the pre-programmed memory region descriptors
— An access protection error is detected if a memory reference does not hit in any memory region
or the reference is flagged as illegal in all memory regions where it does hit. In the event of an
access error, the XBAR reference is terminated with an error response and the MPU inhibits
the bus cycle being sent to the targeted slave device
— 64-bit error registers, one for each XBAR slave port, capture the last faulting address,
attributes, and detail information
1. EBI not available on all packages and is not available, as a master, for customer.
Содержание MPC5644A
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Страница 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Страница 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Страница 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Страница 130: ...Device Performance Optimization MPC5644A Microcontroller Reference Manual Rev 6 130 Freescale Semiconductor...
Страница 204: ...Multi Layer AHB Crossbar Switch XBAR MPC5644A Microcontroller Reference Manual Rev 6 204 Freescale Semiconductor...
Страница 212: ...Peripheral Bridge PBRIDGE MPC5644A Microcontroller Reference Manual Rev 6 212 Freescale Semiconductor...
Страница 558: ...System Integration Unit SIU MPC5644A Microcontroller Reference Manual Rev 6 558 Freescale Semiconductor...
Страница 582: ...Frequency modulated phase locked loop FMPLL MPC5644A Microcontroller Reference Manual Rev 6 582 Freescale Semiconductor...
Страница 766: ...Enhanced Time Processing Unit eTPU2 MPC5644A Microcontroller Reference Manual Rev 6 766 Freescale Semiconductor...
Страница 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Страница 1236: ...System Information Module and Trim SIM MPC5644A Microcontroller Reference Manual Rev 6 1236 Freescale Semiconductor...
Страница 1250: ...Cyclic Redundancy Checker CRC Unit MPC5644A Microcontroller Reference Manual Rev 6 1250 Freescale Semiconductor...
Страница 1336: ...Deserial Serial Peripheral Interface DSPI MPC5644A Microcontroller Reference Manual Rev 6 1336 Freescale Semiconductor...
Страница 1388: ...Enhanced Serial Communication Interface ESCI MPC5644A Microcontroller Reference Manual Rev 6 1388 Freescale Semiconductor...
Страница 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...
Страница 1624: ...FlexRay Communication Controller FlexRay MPC5644A Microcontroller Reference Manual Rev 6 1624 Freescale Semiconductor...
Страница 1670: ...JTAG Controller JTAGC MPC5644A Microcontroller Reference Manual Rev 6 1670 Freescale Semiconductor...
Страница 1692: ...Nexus Port Controller NPC MPC5644A Microcontroller Reference Manual Rev 6 1692 Freescale Semiconductor...
Страница 1701: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 Freescale Semiconductor 1701...
Страница 1702: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 1702 Freescale Semiconductor...