Problems with PCI-CardbusCard (interface is an FPGA) on Wind

[Joachim Mann]

Dear all,
I have one big problem with my cardbus PC-card.
I developed this card on my own and a collegue developed the driver. The
CardBus-interface is included in an FPGA APEX20K100E.
Since there were some statements in the Specifications about burst read, I
adapted
everything on this card for this burst read. But when I insert the card in a
Notebook and read my memory space, no burst happens. All what is done are
normal single accesses. What do I have to do to perform a burst read? Are
there any settings which have to be made to enable such a burst?
My PC-Card is burst-read capable and on the PCI-to-CARDBUS-Bridge I also set
the MBURSTUP and MBURSTDN-Bit to enable such burst. The sys-driver itself
should also be burst-capable I think.

I would be very pleased if anyone could help me solving this problem.
Thanks in advance

Joachim

 

[Nial Stewart]

Joachim Mann <jogges@web.de> wrote in message
news:bm5j3v$h2vjr$1@ID-199325.news.uni-berlin.de...

Dear all,
I have one big problem with my cardbus PC-card.
I developed this card on my own and a collegue developed the driver. The
CardBus-interface is included in an FPGA APEX20K100E.
Since there were some statements in the Specifications about burst read, I
adapted
everything on this card for this burst read. But when I insert the card in
a
Notebook and read my memory space, no burst happens. All what is done are
normal single accesses. What do I have to do to perform a burst read? Are
there any settings which have to be made to enable such a burst?
My PC-Card is burst-read capable and on the PCI-to-CARDBUS-Bridge I also
set
the MBURSTUP and MBURSTDN-Bit to enable such burst. The sys-driver itself
should also be burst-capable I think.

I would be very pleased if anyone could help me solving this problem.
Thanks in advance

Joachim

Joachim,

I've read that PC hosts won't perform burst reads from target PCI cards.
If you want a burst transfer you've got to implement a PCI master/target
in your interface so the master can perform the burst transfer.
I don't think this is mentioned in the PCI spec.

I presume this is the same for Cardbus.

Can anyone else confirm this?


Nial.

------------------------------------------------
Nial Stewart Developments Ltd
FPGA and High Speed Digital Design
www.nialstewartdevelopments.co.uk

 

[Eric Crabill]

Hi,

For both PCI and CardBus (which is basically point-to-point
3.3v, 33 MHz PCI) the host bridges are traditionally very
good targets but not good initiators.

This means that if you want to move lots of data, the way
you need to do it is by making your add-in card become a
bus master, and then read/write host memory.

If you are trying to have the "CPU" read/write the add-in
card, you'll get poor performance. As the original poster
noted, the host won't even burst...

Eric