On Wed, Jun 28, 2017 at 11:02 AM, Noel Chiappa via cctalk < cctalk@classiccmp.org> wrote:
> > From: Josh Dersch > > > I pulled the ... bootstrap boards from slot 3 ... The BOOT button > > causes the RUN light to momentarily flash, but that's about it. > > That's not too surprising. The way booting works with the M9301 boot card > (not > sure if you know this already; if you do, apologies, and ignore) is that > the > 'BOOT' button simulates a power-fail/restart - i.e. it toggles the 'power > OK' > line (forget whether it's ACOK or DCOK). When the CPU 'powers up', and > tries > to fetch the power fail restart vector from 024/6, the M9301 steps on the > bus > address lines and modified the address to 773024/6, which is in the ROM on > the > M9301. The new PS/PC retrieved at that point then sends the CPU into the > ROM. > So, with no M9301 plugged in, it's not too surprising it doesn't do much. > Yeah, I'm aware (or at least was somewhat aware at one point...) of how this works. I'm just surprised the CPU upgrade board doesn't do something similar to provide bootstraps, etc. (Or maybe it can -- there are a lot of jumpers and dip switches...) > > The DEC QBUS processor cards (not sure about the chips themselves) can be > jumpered on power-up to i) halt, or ii) fetch a PS/PC from 024/6, or iii) > jump > to ROM. I've no idea if this board set has something similar (and if so, > what > it's set to do). > > > Ran the front panel cable to the connector on the CPU board and > powered > > it up. > > Now I'm confused. There is no cable from the front panel to the CPU in a > standard 11/34? (There's one from the front panel to the backplane; another > from the front panel to the M9301; and another from the programmer's front > panel [if present] to the programmer's front panel board, the M7859; but > that's it, that I know of.) > Front panel to the CPU upgrade, not the original CPU. If you look at the pictures I posted, there's a pair of connectors on the CPU board that look suspiciously like those on the M7859. There doesn't appear to be an analog for the M9301 cabling, however. - Josh > > Did you mean the console serial line cable? > > Noel >
