xc2234l-20f80l Infineon Technologies Corporation, xc2234l-20f80l Datasheet - Page 36

• Manufacturer Part Number: xc2234l-20f80l
• Description: Lim 16/32-bit Single-chip Microcontroller With 32-bit Performance Xc2000 Family / Econo Line
• Manufacturer: Infineon Technologies Corporation

PRELIMINARY
3.3
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
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.
Data Sheet
Memory Protection Unit (MPU)
Memory Checker Module (MCHK)
32
XC2000 Family / Econo Line
Functional Description
XC2230L, XC2234L
V1.0, 2010-12