RE: BAR value of zero?

[Brooks Lame <Brooks_Lame@mcg.mot.com>]

> -----Original Message-----
> From:	Erin Hunter [SMTP:Erin_Hunter@spectrumsignal.com]
> Sent:	Tuesday, 26 May, 1998 08:26
> To:	Mailing List Recipients
> Subject:	BAR value of zero?
> 
> Hi,
> 
> In section 3.2.2, Addressing, of the PCI spec 2.1 there is a brief
> mention of a base address register value of zero being invalid (the
> comment is in the implementation note on Device Address Space).  Is
> there any more information on this subject in the spec?  How is a PCI
> core supposed to respond if it is assigned a base address value of
> zero?
	[Brooks]  It's not; that's the point and that's how you disable
individual BARs - set them to zero.  On a related subject, FFFFFFFFh
_is_ a valid assignment for a BAR and a PCI device should accept that
value in a config cycle, even though some bits may not be implemented in
it's address decoder.

> Thanks for the help
> Erin Hunter
> 
> Erin_Hunter@SpectrumSignal.com
> Spectrum Signal Processing
> 100 - 8525 Baxter Place
> Burnaby, BC V5A 4V7
> (604) 421 - 5422
[Brooks]  --
Design Engineer                                   Std Disclaimer: 
Motorola Monterey Design Center	                  Opinions expressed 
brooks_lame@mcg.mot.com                           are not necessarily 
blame@prolog.com                                  those of my employer.
>