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Message
From: Mark McDougall<markm@v...>
Date: Fri May 20 03:34:57 CEST 2005
Subject: [oc] DMA core question
Currently I've got an architecture that only DMAs between slaves on
interface #1 of the DMA core. Interface #0 has its slave side connected
to a PCI bus master and the master side is not connected (as the DMA
core is not currently mastering anything on i/f #0).
However, I may need to implement external descriptors - which only fetch
from i/f #0. Problem is, the PCI slave that will source the descriptors
is currently attached to i/f #1 as it is currently the source/target of
DMAs on that interface.
I was wondering if it is possible to connect the master side of the DMA
i/f #0 up to the slave bus on i/f #1 side solely for fetching external
descriptors? i.e. *both* the DMA master units (i/f #0 & 1) would be on
the same bus - without an arbiter. Can I be guaranteed that there'd
*never* be bus contention between the master units - as the core is
either doing a DMA, or fetching descriptors - never both?!?
I'm guessing this is possible b/c you can DMA to/from i/f #0 whilst
using external descriptors and it all works?!?
Regards,
--
Mark McDougall, Software Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266
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