Chapter 32 Cyclic Redundancy Check (CRC)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
805
Chapter 32
Cyclic Redundancy Check (CRC)
32.1
Introduction
The Cyclic Redundancy Check (CRC) computing unit is dedicated to the computation of CRC, thus
off-loading the CPU. The MPC5602P CRC supports two contexts. Each context has a separate CRC
computation engine in order to allow the concurrent computation of the CRC of multiple data streams. The
CRC computation is performed at speed without wait states insertion. Bit-swap and bit-inversion
operations can be applied on the final CRC signature. Each context can be configured with one of two
hard-wired polynomials, normally used for most of the standard communication protocols. The data
stream supports multiple data width (byte/half-word/word) formats.
32.1.1
Glossary
•
CRC: cyclic redundancy check
•
CPU: central processing unit
•
DMA: direct memory access
•
CCITT: ITU-T (for Telecommunication Standardization Sector of the International
Telecommunications Union)
•
SW: software
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WS: wait state
•
SPI: serial peripheral interface
32.2
Main features
•
2 contexts for the concurrent CRC computation
•
Separate CRC engine for each context
•
Zero-wait states during the CRC computation (pipeline scheme)
•
2 hard-wired polynomials (CRC-16-CCITT and CRC-32 ethernet)
•
Support for byte/half-word/word width of the input data stream
32.2.1
Standard features
•
IPS bus interface
•
CRC-16-CCITT
•
CRC-32 ethernet
32.3
Block diagram
shows the top level diagram of the CRC unit.