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?

>>- 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

-- 
Chris Jones - chris@martin-jones.com
Martin-Jones Technology Ltd, makers of Solidlights
148 Catharine Street, Cambridge, CB1 3AR, UK
Phone +44 (0) 1223 474968 Fax +44 (0) 870 112 3908
http://www.solidlights.co.uk/