|
Message
From: Austin Franklin<austin@d...>
Date: Mon Aug 2 08:01:59 CEST 2004
Subject: [pci] PCI Core without Wishbone Interface?
Dan,> My point on the Xilinx license is this: They sell hundreds of
> licenses a year easily.
> The one project license is $2000, the unlimited license is $7000.
> That I don't disagree
> with. But that is still a one year license. Each year you have
> to renew, I talked to
> their rep.
I believe that your information is in error. I believe that once you buy a
version of the core, for your one project use, you have unlimited use of
that core, and only your ACCESS to the core on the Xilinx web site is
"terminated" after one year, not your ability to use what you already have.
I *may* be wrong, and I will find out.
> In regards to your question, its for a PCI card, so it needs to
> be both target and
> master (target for configuration mainly).
As a note, though target is basically the same as configuration, there are
differences. You may also need the target to program the DMA (see below).
> It needs mastering and
> burst capabilities to
> transfer from a 512K onboard cache to system memory.
Most PCI cores (including the Xilinx one), though they provide master
capability, they do not provide the DMA. The DMA is typically "custom", so
keep in mind, you may have to provide that logic as well.
> I guess really what its doing is besides
> for configuration
> registers, its transfering data back and forth between the
> on-board buffer memory
> and system memory.
What OS you are using may influence your DMA architecture. I have typically
made scatter/gather DMA engines (the PLX-9080 offers a rather good DMA
architecture IMO), with the DMA linked list table kept in on-board memory,
and that increases speed significantly. NT typically only gives you 4k
transfers at a time, so for 512k, you would need 128 entries.
Also, what is your data rate? Do you need to run 33 or 66, and 32 or 64
bits? Keep in mind, the timing requirements for 66MHz PCI are difficult,
and you will need a rather fast speed grade. What technology FPGA are you
considering? Sounds like a Virtex 400?
> Sorry about the earlier remarks, I didn't take your previous
> comment as you
> expected and lashed back at you.
Apology accepted.
Regards,
Austin
|
 |
Browse
