> Perhaps a special purpose register on
> the I2C master (and in this case only) controller? That being the case,
> could we not just read the values? I'm assuming the trick is knowing
> if/where they are stored.

i2c detail is invisible.  Control/data protocol is defined by
ACCESS.bus.  ULTRIX runs complicated work to send/receive ACCESS.bus
packets back and forth with great efforts.

Tohru Nishimura