Unibus questions

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed Sep 24 17:31:23 2003

"Doc Shipley" <doc_at_mdrconsult.com> wrote:
> OK. Sanity check. A slot with an adapter using DMA needs the NPG
> grant line *removed*, and if the board in place needs it in place. Does
> breaking the NPG grant for a DMA adapter break the grant for succeeding
> cards?

There are three kinds of SPC modules:

1) Uses NGR - requires NPG jumper to be removed from backplane

2) Does not use NPR, and doesn't pass NPG via a trace - requires
        that the NPG jumper be installed in backplane

3) Does not use NPR, and passes NPG via a trace - doesn't matter
        whether NPG jumper is installed in backplane

Empty slots require either the NPG jumper OR a G727 or G7273 grant
module.

If ANY slot in the backplane does not pass grant properly (either via
a jumper or through a module), you will have problems.

If you have a module that uses NPR, and also have an NPG jumper
installed in the same backplane slot, you will have problems.

> And, does that mean that all the 4x4 slots in the system chassis are
> Qbus, as in I can run an RQDX3?

Running Qbus devices in the 84 will interfere with the Unibus interface.
The 84 doesn't use true Qbus; it is hardwired for a modified Qbus for
use only with the Unibus interface.
Received on Wed Sep 24 2003 - 17:31:23 BST