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Message
From: Rudolf Usselmann <rudi@a...>
Date: 03 Jun 2003 19:39:31 +0700
Subject: Re: [usb] USB1.1 Core Address Assignment Failing. Debuggingsuggestions?
On Tue, 2003-06-03 at 20:02, Evan Jones wrote:
> I'm a little embarrassed now. Just 1 day after posting my original
> request for help, we got the thing working!
>
> On Tuesday, Jun 3, 2003, at 05:05 Canada/Eastern, Rudolf Usselmann
> wrote:
> > Function address 0 seems to be strange. Never have seen that ...
>
> Well, the bizarre errors that we were seeing were caused by some
> strange interactions between the
>
> We eventually realized the problem because we were reading the "state"
> variable inside usb_ctrl.v, and it never changed. It turns out that
> when we examined the compile messages, it was being detected as being
> stuck at ground, and optimized away. The problem was that when we were
> intitially compiling the core for our Altera APEX 20K200E, the Quartus
> II software reported it as not meeting the timing constraints. Then we
> found the "VENDOR_ALTERA" define (I can't remember which file exactly
> now) and after setting that, it compiled MUCH faster (because it was
> optimizing away a bunch of critical things). After all our furious
> debugging, we started with the USB1.1 function controller source from
> scratch and it compiled fast enough the first time, and worked the
> first time!
This is great news ! I'm glad it worked out !
> The important question now is, is that "VENDOR_ALTERA" setting
> supposed to work on the APEX 20K200E chip? Because it doesn't appear to.
Ahh, this is probably in the "generic_memories.v" file. It's
actually something I did not write, but if I remember correctly
it supposed to allow you to select the appropriate, optimized
built in memories for several FPGAs (Xilinx & Altera) and also
for a few ASIC libraries. It might be that the selection mechanism
is broken or that Quartus is broken (more likely in my opinion :*).
> Thank you for your assistance, and for the USB1.1 core. Once we get the
> system working more thoroughly, we will be submitting some
> documentation for the core.
>
> Evan Jones
Cheers !
rudi
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