Yes, I have +NVMREG under Errata
No idea about the cast really. I guess it was needed for the old MPLAB compiler? Seems to compile OK in XC8 without.
Anyway.. It suddenly started working?
The snippet above was something I broke out into an easily accessible place. The original code was:
gpib_flags = gpib_flags & ~FLAGS_EOI; // No EOI
gpib_flags = gpib_flags | FLAGS_EOI; // EOI on
gpib_flags = gpib_flags & ~FLAGS_EOI;
What happened was that the ControllerDescription was sent, but the two other ended up as all zeroes.