restoring .ptf files & reference designs

Hi Jim,

Unfortunately no, the .ptf file is the single file SOPC Builder reads/writes to determine a system. The schematic symbol is created from a script that examines the signals on the top level of the HDL generated.

You might take a closer look for files called ".ptf.bak" or ".ptf.401" or similar.... that is assuming you started a design way back when with a previous version of SOPC Builder and opened it with a new SOPC Builder version along the way; depending on the versions involved a backup copy of the old PTF is saved.

As far as example designs -- we have a suite of HW example designs that go out with each version. You can download the Nios II evaluator (if you don't already have it) and it will have the example designs (PTFs included) for all current Nios II designs. If you have a specific request for an example design from something like Nios 3.2, feel free to contact me...