Re: Legacy Terminology RE: DMA across PCI

[Ted Firlit <firlit@utmc.aeroflex.com>]

I'm using a Galileo PCI controller chip (GT64120A) which specifically
implements a 4-channel DMA engine for the host CPU to set up DMA
transfers.  I didn't think this was so unusual for a PCI controller chip
to do.  If and when we change out this chip, I'll expect the replacement
to implement DMA as well,  unless you know something about DMA and PCI
which I don't.

TedF

Lame Brooks-G14738 wrote:
> 
> Yeah, years ago when I was a newbie to PCI, I got smacked on the head for
> using DMA in reference to PCI.  DMA is an ISA bus related acronym that
> stands for Direct Memory Access.  PCI is by definition all about direct
> memory access - that's one of the features that made it superior to ISA!
> Therefore, the old term DMA itself has little meaning in reference to PCI.
> I think most of the people who try to use it now days are meaning a concept
> analgous to the legacy ISA DMA Transfer Engine which is simply a state
> machine that can manage a block data transfer given the start and end
> addresses.  I'd stay away from legacy terminology when talking about
> specific bus behaviour like burst transfers.   -- BrooksL
> 
> -----Original Message-----
> From: Daniel DeConinck [mailto:daniel.deconinck@sympatico.ca]
> Sent: Saturday, 14 October, 2000 09:48
> To: pci-sig@znyx.com
> Subject: DMA across PCI
> 
> Hello,
> 
> I looked in the index of the PCI spec 2.1 and the index of "PCI System
> Architecture", by Mindshare, Inc. Niether had a reference to DMA.
> 
> I am guessing that there is no such thing as DMA in the PCI world. Is that
> the case ?
> 
> I further guess that the closest thing to DMA is a Master read or a Master
> write cylce.
> 
> Please enlighten me.
> 
> Sincerely
> Daniel DeConinck
> High Res Technologies, Inc.
> 
> 

-- 
Ted Firlit		      		(719) 594-8138
Senior Design Engineer
UTMC Microelectronics Systems
4350 Centennial Blvd., MS 1004
Colorado Springs, CO 80907