QBUS VAX and M7941 under VMS - info needed!

From: Dave Woodman <dave_at_naffnet.org.uk>
Date: Fri Apr 19 01:46:09 2002

Carl Lowenstein wrote:

> > From owner-classiccmp_at_classiccmp.org Thu Apr 18 15:17:12 2002
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> > Date: Thu, 18 Apr 2002 22:38:24 +0100
> > From: Dave Woodman <dave_at_naffnet.org.uk>
> > Organization: The Nicely Naff Network
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> > To: classiccmp_at_classiccmp.org
> > Subject: QBUS VAX and M7941 under VMS - info needed!
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> > Sender: owner-classiccmp_at_classiccmp.org
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> >
> > Hi all,
> >
> > I have a MicroVAX (BA123 enclosure, KA650 CPU) that I would like
> > to put to work... to this end I have two M7941 (DRV11) parallel I/O
> > cards that I would like to bring into service. The Micronotes say that
> > this card is compatible with the 22-bit QBUS, and I have the Field
> > Service print set so I can set the CSR and vectors to appropriate
> > values.
> >
> > Of course, VMS does not have a driver for these cards, but I am
> > not too frightened by the prospect of a little code - here lies the
> > problem! Can anyone tell me just how this card maps into the I/O space,
> > given the CSR? I would like to know just where to read from and write to
> > in order the drive the beastie...
>
> It's sort of standard DEC for a parallel interface.
>
> CSR + 2 is the output buffer, connected to connector J1
> Bits in CSR+2 are read/write to the CPU
> besides the data lines, J1 has some control bits
> REQA which maps to CSR<15> and is read-only
> NEWDATA, pulse output by CPU writing to CSR+2,
> which should be used to clear REQA
> CSR1 which is CSR<1>, read-write for device control
>
> CSR + 4 is the input buffer, connected to connector J2
> Bits in CSR+4 are read-only to the CPU
>
> J2 has control bits:
> REQB mapped to CSR<7>, read-only
> DATATRANS, pulse output by CPU reading CSR+4,
> should be used to clear REQB
> CSR0 which is CSR<0>, read-write for device control
>
> CSR has the usual INT_ENB A at <6> and INT_ENB A at <5>
> INT_ENB AND REQ makes an interrupt. Interrupt A at VEC, B at VEC+4.
>
> Information from "microcomputer interfaces handbook 1980"
> EB-17723-20
>
> carl
> --
> carl lowenstein marine physical lab u.c. san diego
> clowenstein_at_ucsd.edu

Thanks Carl, for this and the later post.

Hmm, Microcomputer Interfaces Handbook... IS this venerable document on line anywhere? I am guessing that it's
aimed at the PDP11 et al, but Q-22 is Q-22, even if it is using older cards.

    Cheers,

        Dave.
Received on Fri Apr 19 2002 - 01:46:09 BST