Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

5.3. Alternative Nios® II Boot Methods

In any stand-alone embedded system that contains a microprocessor, the processor runs a small piece of code called a boot copier, or boot loader, after the system resets. The boot copier locates the appropriate application software in non-volatile memory, copies it to RAM, initializes critical system components, and branches to the entry point of the application software image. The block of data in non-volatile memory that contains the application software is commonly referred to as the boot image. Boot copiers range in complexity from basic byte-for-byte copy routines to comprehensive applications that perform rigorous system tests, select among multiple software applications, and unpack, decompress, and perform error detection on the proper application.

This document teaches you how to implement your own custom boot copier software using the Nios® II processor and Nios® II software build tools. In addition, this document provides the basic information needed to externally control the Nios® II boot process.

This document addresses how to implement a custom boot copier for a Nios® II processor already configured in the FPGA. It does not address custom methods of configuring Intel® FPGAs.

For information about custom methods for configuring Intel® FPGAs, refer to the "Configuration Solutions" web page on the Intel FPGA website.