Re: PCI CLKS disabled relating to FPGA controllers ??

[Meindert Kuipers <meindertk@aexpo.com>]

 From my experience with VMETRO's PCI Analyzer is looks like at least the 
IDSEL must be connected, and that the device must respond to config cycles. 
I assume that the BIOS does config cycles to all slots, and 'empty' slots 
have their CLK disabled. If your device is behind a bridge, the same 
mechanism might apply, depending on the type of bridge.
If your FPGA is not configured, it will not respond to config cycles, and 
the system assumes an empty slot. Note that the spec defines a time after 
which a device MUST respond to config cycles after the release of RESET#, I 
think it is about 1/2 a second.
I you must load your device from the bus, it looks that you really depend 
on the motherboard type ....

Meindert Kuipers


At 09:21 29-6-00 -0400, you wrote:
>Hello,
>
>Regarding: PCI CLKs turning off in unused slots.
>
>Can a PC incorrectly judge a slot to be unoccupied if that slot contains a 
>FPGA controller which needs some time to configure ? OR do PCs always only 
>use the 'card present' signal to determine if a slot is occupied.
>
>Sincerely
>Dan DeConinck
>
>
>