Darnit! UDA50 problem.

From: Daniel A. Seagraves <dseagrav_at_bsdserver.tek-star.net>
Date: Tue Nov 4 09:36:59 1997

On Tue, 4 Nov 1997, Tony Duell wrote:

>
>
>
> If you can boot RT11, then the grants must be continuous. Is the RX211
> nearer the CPU than the UDA50? Normally, if you've left an NPG jumper in
> where you shouldn't have, then the devices past that point fail to do
> NPR's correctly.

It's closer.

>
> >
> >
> > You don't mean the CGJ card, do you? There's something else I'm supposed
>
> No, I mean on the backplane. The little single-height continuity cards
> only connect the bus grants. The dual-height ones do the NPG signal as
> well, _but_ the jumper I mentioned below is still fitted, since a lot of
> older cards do not short CA1 to CB1 themselves, so the wire-wrapped link
> is need if you use one of those cards.
>
> > to have screwed with. You mean I have to cut one of the wire-wraps on the
> > backplane? That doesn't sound like a good idea... is that correct? When
>
> Absolutely. The wire in question is between pins CA1 and CB1 on the _same_
> slot - the slot the control cart of the UDA50 is in. It's a little loop of
> wire, and is quite difficult to find the first time.

Okay... I'll give it a shot! But if I foul up, I'm stuck - I don't have
a wirewrap tool.

>
> When I re-wrap them (say after removing a card), I normally use red wire
> to make them easier to spot the next time.
>
>
> The jumper shorts NPGin to NPGout on the slot. It must be fitted on slots
> that do not contain options that use DMA (either empty slots, or slots
> that contain options that use programmed I/O only - like DL11's, DR11-C's,
> etc). It must be removed on slots that contain DMA options (like the
> UDA50). If you just pulled a single-height grant card and fitted the UDA50
> card, then I am _sure_ you need to cut this jumper as well. Otherwise
> NPGin is shorted to NPGout on the UDA50 and the internal grant logic goes
> crazy on this card (it won't do any damage, though).

Oh! That's what's happening... OK, I'll go look at it.
Thanks!
Received on Tue Nov 04 1997 - 09:36:59 GMT