Using Previously Installed Versions of the Nios® II EDS and Quartus® II Tools
SOPC Builder and the Nios II IDE refer to the most recently installed version of components (such as the Nios II processor and peripherals) and their software drivers. To revert to a prior version of the Nios II development tools, you can reinstall the previous version of tools or modify the following environment variables.
. SOPC_BUILDER_PATH - Ensure that SOPC_BUILDER_PATH points to the installation directory of the desired Nios II version and no other Nios II versions. SOPC_BUILDER_PATH should also contain the paths of other IP, separated by a " ".
. SOPC_BUILDER_PATH_<version> - Ensure that SOPC_BUILDER_PATH_<version> points to the installation directory of the corresponding Nios II version. This is necessary only for versions 6.0 and 5.1. Exclude the period in <version>, for example, use SOPC_BUILDER_PATH_60
. SOPC_KIT_NIOS2 - Ensure SOPC_KIT_NIOS2 points to the installation directory of the desired Nios II version and no other Nios II versions.
Finally, launch the corresponding version of Quartus II to ensure that the QUARTUS_ROOTDIR environment variable is updated. Then exit Quartus II before using any tools in the switched version, including Quartus II.
For the Windows version, there is a batch script called Altera_Tool_Switch.bat, along with a special version of setenv.exe which can update system variables. They are available in the zip file Altera_Tool_Switch.zip.