Information

Chapter 30
Cyclic Redundancy Check (CRC)
30.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration chapter.
The cyclic redundancy check (CRC) module generates 16/32-bit CRC code for error
detection.
The CRC module provides a programmable polynomial, WAS, and other parameters
required to implement a 16-bit or 32-bit CRC standard.
The 16/32-bit code is calculated for 32 bits of data at a time.
30.1.1 Features
Features of the CRC module include:
• Hardware CRC generator circuit using a 16-bit or 32-bit programmable shift register
• Programmable initial seed value and polynomial
• Option to transpose input data or output data (the CRC result) bitwise or bytewise.
This option is required for certain CRC standards. A bytewise transpose operation is
not possible when accessing the CRC data register via 8-bit accesses. In this case, the
user's software must perform the bytewise transpose function.
• Option for inversion of final CRC result
• 32-bit CPU register programming interface
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 571