RE: <OFFTOPIC>? How to achieve a long burst

[Lame Brooks-G14738 <brooks.lame@motorola.com>]

Hi Peter; in my experience, it quickly gets confusing trying to describe
these complex architectures and correctly answer these kinds of questions -
you may get various answers from people who are understanding your question
differently.  Terms like CPU, PRIMARY, SECONDARY, HOST, and SLAVE can become
ambiguous.  The best thing to do is open up the .PDF 21554 data sheet file
to read the description of the register bit and apply it to the context of
your application.  Labeled block diagrams work wonders in communicating
system arch.  Good luck.  -- BrooksL

> -----Original Message-----
> From: Schaefer, Peter [mailto:Peter.Schaefer.tiscon_ag@vs.dasa.de]
> Sent: Thursday, 14 December, 2000 06:58
> To: pci-sig@znyx.com
> Subject: Re: How to achieve a long burst <OFFTOPIC>?
> 
> 
> Dear all!
> 
> > Unfortunately, it appears that the bridge chips on PC 
> motherboards do
> > not implement DMA engines.  Therefore it falls to the peripherals to
> > implement DMA.. which also mandates they must be capable of 
> > becoming the PCI bus master. 
> 
> Let me take this as a opportunity to answer a question:
> 
> What's needed to become a PCI bus master?
> We have a processor board that hides behind a 
> non-transparent Intel 21554 bridge, therefore 
> seen as a device from the host CPU. The bridge
> cannot be arbiter of the primary bus the host 
> CPU is on but supports the "Master Enable"-Bit
> on this side. Would it be sufficient to set this
> bit to enable the "Slave-CPU" on the secondary side
> of the bridge to do Busmaster-DMA?
> 
> Thanks a lot - an sorry to be offtopic.
> 
> 
> Regards,
>    Peter
> 
> -- 
> peter.schaefer@gmx.de
> 
>