Re: firewire bus/card counter

George Morgan wrote:
> Quoting Stefan Richter <[email protected]>:
>> It is highly unlikely that there are any commercially available dual
>> controller cards for PCMCIA (CardBus actually) or ExpressCard, although
>> it seems feasible, especially in case of ExpressCard with the recent
>> generation of PCIe 1394 link & PHY chips with their small footprint.
> 
> There are probably several issues with making either a cardbus or  
> expresscard dual controller cards:
> 
> 1)  [Power]
...
> 2)  [Space] Cramming two controllers and possibly a needed PCI-PCI  
> bridge into a cardbus or expresscard form-factor is also a challenge.   
> If there was a vendor that came up with an integrated solution then  
> that would be a possibility but that would require custom silicon  
> which would probably only be used in this application which would  
> probably prove to be too costly.
> 
> 3) [Interrupt Request Lines]
...

Space and power aren't a problem with chips like this one: 
http://www.lsi.com/networking_home/networking_products/p1394_products/fw643/
They manufacture (11mm)² or (7mm)² packages and specify 3.3V power 
supply and less than 0.6W typical power dissipation.  ExpressCard 
supplies 1000mA "average" at 3.3V (plus 250mA at 3.3V aux plus 500mA at 
1.5V, 1750mA maximum combined at all rails).

I don't know what's up with interrupt lines in case of ExpressCard ( = 
single lane PCIe) but there is no fundamental reason against sharing an 
interrupt between 1394 link layer controllers if the drivers aren't broken.

Still, a dual link 1394 card would be a niche product, hence I don't see 
it becoming available in ExpressCard form factor anytime soon.
-- 
Stefan Richter
-=====-==--= -=== ----=
http://arcgraph.de/sr/

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