Re: [Balloon] Balloon 3 Samtec pinout - first proposal

On Wednesday 22 June 2005 5:13 am, Chris Jones wrote:
> Steve Wiseman wrote:
> >>The changes from Balloon 2 are:
> >>- VDD_3V is now VDD_IO (still a 3.3V supply)
> >>- VDD_5V is now VDD_RAW (which is 'rough' 5V)
> >
> > Well, sort of. If you feed 5V in, it'll be 5V... If you strap it to a
> > lithium cell, it won't be.
> > Bear in mind that these pins could as easily be used to feed power into
> > the balloon, as to feed power from the Balloon to the other board -
> > depends if you see the board as a backplane or an expansion card, really.
>
> Yes, agreed.
>
> > We don't need nSDCAS<0..3> (pins 1, 3, 5, 7)
> > They make no sense on the backplane. (rummage. They should be DQM<0..3>)
>
> Good point. I did wonder about them, given the lack of other
> SDRAM-related signals, but NCAS0/1/3 don't feature on the (slightly
> ambiguous) list of things that Guralp definitely aren't using, so I
> didn't meddle with them. It's hard to see what they'd be using them for,
> anyway.
>
> DQM3..0 would be much more useful, I agree. Can anyone from Guralp
> (James McKenzie?) comment?
What's the diffference between the NCAS0.. and DQM0..? I use the NCAS0 on my
mother board.
>
> >>- MBREQ/DREQ<0> and MBGNT/DVAL<0> are present on the Samtec so
> >>motherboard devices can do bus mastering and DMA
> >
> > I guess I ought to pull these to a safe state on Balloon :)
>
> I'm sure we'll be discovering myriads of things like that...
>
> Chris