PDP-11/05 (was: PDP-11/05 microcode dump?)
uban at ubanproductions.com
Mon Jun 14 08:19:11 CDT 2021
Thanks Bill, nice read. Did you get your RK11/RK05 up and running on the 11/05?
My 11/05s both have the low profile side mounted chassis, which I find makes them nice and compact,
but limits their expansion without another cabinet.
On 6/13/21 3:59 PM, Bill Degnan wrote:
> It's no gunkies but I wrote up a few notes about my 11/05 variants and support issues here:
> https://www.vintagecomputer.net/digital/ <https://www.vintagecomputer.net/digital/>.
> On Sun, Jun 13, 2021, 4:44 PM Tom Uban via cctalk <cctalk at classiccmp.org
> <mailto:cctalk at classiccmp.org>> wrote:
> I am working on the first of my two 11/05s. Interestingly, it has the early version M7261E Control
> Logic & Microprogram board and the later version M7260 Data Paths board (with circular baud rate
> selector switch) as described in:
> http://gunkies.org/wiki/KD11-B_CPU <http://gunkies.org/wiki/KD11-B_CPU>
> >From the description there, it seems like an older/newer combination, but maybe that was
> common. I
> would not have guessed that the four possible combinations would all work together, but maybe
> they do?
> I have a couple different drawing sets for the 11/05 and while some have the matching M7260
> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E schematic:
> The GT40 drawings has the PROM listings and related, so I am hoping that they match what is in the
> two boards.
> Presently, the machine sometimes runs relatively well and other times it does not. It does
> have bit
> 1 stuck ON in memory, but that should be a relatively simple task to diagnose as it is not
> intermittent. When the machine is "working" I am able to deposit 0777 at 0100 and run. When
> this simple program, I've experimented with flexing the boards and such, so it doesn't seem
> like an
> obvious poor connection, but that remains to be seen.
> The machine is a configuration #2 model (as described in the "gunkies" site) and my initial
> with KM11 boards, reveals that I can step the microcode with a KM11 in either the #1 or #2
> but when two KM11s are installed at the same time, they do not function properly together. Is this
> expected or do I have an issue there too?
> Thanks much to those who have provided details and documents on the web, they have already been of
> great value and will most certainly continue to be a resource in the future.
> More updates in the future...
> On 5/6/16 5:32 PM, Noel Chiappa wrote:
> > > From: Mattis Lind
> > > Thanks Noel for sorting this out.
> > Eh, de nada. But thank you.
> > >> I wonder if the ucode in the two versions is identical? The uROM chip
> > >> numbers should give it, (if they are the same on both versions, albeit
> > >> in different locations on the board), but I have yet to check. Does
> > >> anyone happen to know?
> > OK, so the situation here is pretty complicated. To start with / make things
> > worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of PROMs.
> > For the data paths board (M7260), both major versions appear to contain the
> > same PROMs (going by the DEC part numbers), but the chip location (Exx)
> > numbers are all different.
> > For the control board (M7261), the C, E ('early' version) and F ('late'
> > version) etch revisions each contain mostly the same PROMs, but apparently
> > with slight differences between the sets of PROMs in each (as reflected in
> > different DEC part numbers). For details see:
> > http://gunkies.org/wiki/PDP-11/05#Control_PROMs
> > to which I have just added all the gory details.
> > As to getting the contents of all of them dumped in machine-readable form -
> > oi vey!
> > >> on the earlier version (prints for that version are in the GT40 prints
> > >> online
> > It turns out that I have hard-copy prints for the "C" etch revision of the
> > M7261, which do not yet appear to be online; the GT40 prints have the "E"
> > etch revision.
> > I will scan the pages for that revision of the board, and put them up 'soon'.
> > (I'm not doing the whole print set, it's about 1" thick, and most of them are
> > for other things anyway, like MM11-L memory, etc.)
> > Noel
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