Yep, fun times on LSI-11/2! Some configurations also won't boot unless it's on, if I remember correctly. I suppose this is part of the reason that LSI-11/2 CPU boards are so cheap!
Thanks, Jonathan On Wed, Aug 14, 2019 at 10:17 AM Noel Chiappa via cctalk < [email protected]> wrote: > > From: Paul Koning > > > Isn't the interrupt disabled by RESET? > > Nope. On the -11/03 and KDF11-A, BEVNT is wired straight into the CPU, and > there's no internal register to control it. > > The BDV11 does have a register which can enable/disable the LTC (it > connects > BEVNT to ground via a transistor when the appropriate register bit is > cleared); but, ironically (given your question), BINIT/RESET does _not_ > clear > that register! Only BPOK does. (My theory is they were short of a bus > receiver > for BINIT, and rather than put a whole extra chip on the card...) So, once > on, > it has to be explicitly turned off, or the 'boot' switch (which toggles > BPOK) > has to be hit. > > The KDF11-B and all KDJ11 machines do have the LTC register, which operates > 'correctly'. > > Noel >
