Nios II Custom Instruction Design Example

This design example shows how to implement the cyclic redundancy check (CRC) algorithm as a Nios® II custom instruction. The CRC algorithm detects the corruption of data during transmission. The CRC calculation consists of an iterative algorithm involving XOR and shift operations. These operations are carried out concurrently in hardware and iteratively in software. Since the operations are carried out concurrently, the execution is much faster in hardware. This example demonstrates the way to implement an extended multi-cycle Nios II custom instruction.

Using This Design Example

To run this example, download the ug_custom_instruction_files.zip and unzip it to your hard drive. Then, follow the instructions in Nios II Custom Instruction User Guide.

The use of this design is governed by, and subject to, the terms and conditions of the Altera Hardware Reference Design License Agreement.

Design Examples Disclaimer

These design examples may only be used within Altera Corporation devices and remain the property of Altera. They are being provided on an “as-is” basis and as an accommodation; therefore, all warranties, representations, or guarantees of any kind (whether express, implied, or statutory) including, without limitation, warranties of merchantability, non-infringement, or fitness for a particular purpose, are specifically disclaimed. Altera expressly does not recommend, suggest, or require that these examples be used in combination with any other product not provided by Altera.