Diagnose AOC: Internal Compiler Error

In AOC version 14.0 and earlier, "Error: Internal compiler Error" means one of the underlying tools (QSYS or QUARTUS) either crashed or produced an error. The best way to diagnose this, as was pointed out before is to check <kernel>.log and quartus_sh_compile.log. Just search for "Error ".

The most likely cause is no-fit in Quartus. This means the kernel is too big. Resource estimator usually does a good job in estimating final resource usage but could be a bit off. Also remember that you can't really fit a 99% full design.

If you see "current module quartus_xxx ended unexpectedly", it's most likely an out-of-memory issue (assuming you didn't just kill the process :) ). Quartus, especially for Stratix V FPGAs, requires a lot of RAM on your PC. Check Quartus Device Support Release Notes (http://www.altera.com/literature/rn/rn_qts_dev_support.pdf). Just to give you an idea, for the smallest Stratix V device you'll need 8GB, going upto 28GB for the largest.

In 14.1, the "internal compiler error" message will be improved somewhat to give you a better idea of the possible causes.