eviefinch wrote
This is my code for RAM512 but I can't see what the error is.
...
Mux8Way8(a=aa, b=bb, c=cc, d=dd, e=ee, f=ff, g=gg, h=hh, sel=address[6..8], out=out);
What's Mux8Way8? The fact that you are not getting a load error makes me wonder if you are loading the .tst file from a different directory than the directory containing this RAM512.hdl.
Other than the Mux8Way8 your code is correct. Please edit your post to remove the HDL.
--Mark