XC2230L datasheet(36/112 Pages) INFINEON

36 / 112 page

XC2230L, XC2234L

XC2000 Family / Econo Line

Functional Description

Data Sheet

V1.3, 2015-02

3.3

Memory Protection Unit (MPU)

The XC223[04]L’s Memory Protection Unit (MPU) protects user-specified memory areas

from unauthorized read, write, or instruction fetch accesses. The MPU can protect the

whole address space including the peripheral area. This completes established

mechanisms such as the register security mechanism or stack overrun/underrun

detection.

Four Protection Levels support flexible system programming where operating system,

low level drivers, and applications run on separate levels. Each protection level permits

different access restrictions for instructions and/or data.

Every access is checked (if the MPU is enabled) and an access violating the permission

rules will be marked as invalid and leads to a protection trap.

A set of protection registers for each protection level specifies the address ranges and

the access permissions. Applications requiring more than 4 protection levels can

dynamically re-program the protection registers.

3.4

Memory Checker Module (MCHK)

The XC223[04]L’s Memory Checker Module calculates a checksum (fractional

polynomial division) on a block of data, often called Cyclic Redundancy Code (CRC). It

is based on a 32-bit linear feedback shift register and may, therefore, also be used to

generate pseudo-random numbers.

The Memory Checker Module is a 16-bit parallel input signature compression circuitry

which enables error detection within a block of data stored in memory, registers, or

communicated e.g. via serial communication lines. It reduces the probability of error

masking due to repeated error patterns by calculating the signature of blocks of data.

The polynomial used for operation is configurable, so most of the commonly used

polynomials may be used. Also, the block size for generating a CRC result is

configurable via a local counter. An interrupt may be generated if testing the current data

block reveals an error.

An autonomous CRC compare circuitry is included to enable redundant error detection,

e.g. to enable higher safety integrity levels.

The Memory Checker Module provides enhanced fault detection (beyond parity or ECC)

for data and instructions in volatile and non volatile memories. This is especially

important for the safety and reliability of embedded systems.

XC2230L Datasheet(PDF) 36 Page - Infineon Technologies AG