1–2 Chapter 1: Overview
Nios II Software Development Environment
Nios II Software Developer’s Handbook © March 2009 Altera Corporation
Preliminary
Finding Nios II EDS Files
When you install the Nios II EDS, you specify a root directory for the directory
structure containing the EDS files. For example, if the Nios II EDS 8.1 is installed on
the Windows operating system, the root directory might be c:\altera\81\nios2eds.
The root directory can be any accessible location in your file system. For simplicity,
this handbook refers to this directory as <Nios II EDS install path>.
1 The Nios II EDS defines the environment variable SOPC_KIT_NIOS2 to represent
<Nios II EDS install path>.
Nios II Software Development Environment
The Nios II EDS provides a consistent software development environment that works
for all Nios II processor systems. With a PC, an Altera FPGA, and a JTAG download
cable (such as an Altera USB-Blaster™ download cable), you can write programs for,
and communicate with, any Nios II processor system. The Nios II processor’s JTAG
debug module provides a single, consistent method to communicate with the
processor using a JTAG download cable. Accessing the processor is the same,
regardless of whether a device implements only a Nios II processor system, or
whether the Nios II processor is embedded deeply in a complex multiprocessor
system. Therefore, you do not need to spend time manually creating interface
mechanisms for the embedded processor.
The Nios II EDS provides two distinct development flows and includes many
proprietary and open-source tools (such as the GNU C/C++ tool chain) for creating
Nios II programs. The Nios II EDS automates board support package (BSP) creation
for Nios II processor-based systems, eliminating the need to spend time manually
creating BSPs. Altera BSPs contain the Altera hardware abstraction layer (HAL), an
optional RTOS, and device drivers. The BSP provides a C/C++ runtime environment,
insulating you from the hardware in your embedded system.
Nios II Programs
Each Nios II program you develop in either Nios II EDS development flow consists of
an application project, optional library projects, and a BSP project. You build your
Nios II program to create an executable and linking format (.elf) file which runs on a
Nios II processor.
The following sections describe the project types that constitute a Nios II program.
Application Project
A Nios II C/C++ application project consists of a collection of source code compiled
to create one .elf file. A typical characteristic of an application is that one of the source
files contains function main(). An application includes code that calls functions in
libraries and BSPs.
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