Memory Stack

• provide non volatile data to the application in a uniform way
• provide mechanisms for non volatile data management like saving, loading, checksum protection and verification, reliable storage etc
• abstract from memory locations and properties

memory technology : Flash : cheap, sector erasable, Faster Write cycles,Slower Erase Cycles EEPROM : Expensive, Byte Erasable,Slower Write cycles, Faster Erase Cycles

Memory Stack Architecture

• Memory block types
  • RAM
  • ROM
  • Nv Data
    • Native physically have one Data block size
    • Redundant physically have two copies of single Data block size
    • Dataset physically have 1 to M Data block size
  • Admin

Stack Modules

NVM (Services Layer)

main features

• provides reading and writing services to the application
• Handles concurrent accesses from all application components
• performs CRC checks

core configurations

• Memory Block Number
• ROM Address(Optional)
• RAM Address(Optional)
• Selection for WriteAll/ReadAll
• CRC Type
• Block Management type (native, Redundant,dataset)

Memif (ECU layer)

• abstraction of the services layer from the type of memory technology used, acts as a router to Flash or EEPROM

EA/FEE

Main Features

• abstracts from the device specific addressing scheme and segmentation
• Provide mapping between virtual and physical Addresses
• Virtual address space of 32bit
• 16bit : a theoretical number of 2^16 of blocks
• 16bit : a theoretical block size of 64Kbyte per block

FEE have extra feature

• the FEE module emulates the same behavior of using EEPROM although physically they are different memory technologies, especially for erasing scheme

• flash erase scheme is by sector, yet in EEPROM it is by byte blocks

Virtual to physical Mapping

you can implement it the way you want because autosar didn’t define a way to implement it

Core Configs

• memory block satisfying the NVM NV Block types
• Ex: Redundant NVM Blocks will result in configuring 2 Fee Blocks
• For each Block, Size configured = Data Size in NVM + Added CRC size configured in NVM

in the FEE we need to configure Native and Redundant Data Blocks

EEP/FIs

• Abstraction of microcontroller registers
• provide services for reading, writing and Erasing fromthe physical memory
• Main configurations would be sctor size, page size and number of sectors(obtained from MC spec sheet)