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LogiCORE PCI-X question

Hi.

  1. After configuration of BAR's, is there a way for the user application code (inside the fpga) to get the BAR's exact value?

  1. Is there a way to set the BAR's values internally ? i.e without a PCI-X configuration cycles ?

  2. I would like to use the PCI-X core prior to the host configuration. I.e after appropriate reset phase, I would like to assert M_REQ of the core and then I expect the core to assert REQ_O. Is this possible?

ThankX, NAHUM

Reply to
Nahum Barnea
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So you're saying you want to initiate a data transfer between the time the system reboots and the BIOS assignes BAR values? For one, that's a little scarry, and for two, the system bus isn't going to be available during that time (where are you going to get/send data with no other devices on the bus?), and for three, I would doubt it is possible. If you need to do a data transfer at that time use some other medium from your board than the PCI-X bus. I believe if you use ports instead of memory registers you can set their exact values. You could pass in the memory registers' addresses when the driver initializes. Give some more detail for your app and we could get you some better suggestions.

Reply to
Brannon King

Hello,

No. Unless you are doing something, well... unusual, your user application should not care about its absolute address -- only that it is being accessed. The LogiCORE PCI-X interface lets you know you are being accessed, but does not let you see your absolute address.

In general, no. However, if you read the chapter in the design guide about setting core options, you will see there's limited support for this involving BAR0 and BAR1.

I would carefully consider what this person wrote, and make sure you aren't trying to do something that will result in a system failure.

Eric

Reply to
Eric Crabill

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