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

Oct 10, 2003 2 Replies
J

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


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N

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set

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

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E

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

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