Basics questions on System ID Peripheral

System ID also prevents you from having a mismatch between your hardware and software configurations. When you compile the software, it stores the system ID of the SOPC Builder/QSYS project at the time of the compile, and when you download the software Eclipse will first check that the configuration in the FPGA has the same ID than the one used to compile the software. That way if you have modified your SOPC project but forgot to recompile the software, you will know it before uploading the software to a potentially incompatible hardware configuration.