Hi Glenn,
At the moment, the dialog box just sets the timing constraints. As you've
discovered it doesn't exert any control over the DCM settings. I think it
would be possible to add this feature to the toolflow, but for the time
being I think you're best off bringing in the clock externally through the
SMA. I'm pretty sure that Matt, Oren, and co. have found a good solution
to the signal level problems and have the appropriate adapter board design
needed to get the clock in cleanly.
If is absolutely necessary to use the DCMs, you can probably hack the
EDK base system, but I would heartily recommend against that...
Thanks,
Henry
G Jones wrote:
Hi,
I've been looking very carefully at the BEE2 clock schematics as I need
to eventually synchronize an iBOB and BEE2. There is a PLL chip that
drives User Clock and a 100MHz oscillator that drives System clock.
There are also jumpers that allow choosing to inject an external clock
on an SMA for either User or System clock. When I asked Chen how to set
the PLL chip he said it was not supported and that I should use the DCM
to generate whatever clock I need from the 100 MHz system clock
oscillator. This is what I am asking about, how to set that up. I just
tried compiling a BEE2 design where I tried setting the option to User
clock and entered 256 MHz frequency and had an LED blink whenever a 27
bit counter rolled over. With the user clock I measured ~ 25 MHz based
on the LED blink rate, which is consistent with the 25 MHz that the PLL
chip uses as it's reference. I then recompiled the same design, but
selected the System clock, but still entered 256 MHz, and this time the
blink rate was consistent with 100 MHz. So it seems that it is NOT
possible to configure the DCM to put out an arbitrary frequency based on
either clock source just by entering that frequency in the MSSGE config
block. Anyone know how to get this to work?
Thanks,
Glenn
On 12/11/07, *Oren Milgrome* < o...@berkeley.edu
<mailto:o...@berkeley.edu>> wrote:
Hi, no clock synthesizer, just a switch for the SMA connector vs 100MHz
oscillator and a switch for the pll clock doubler.
> Hi Oren,
> Thanks for the response. Does that actually configure the DCM to
output
> that
> clock rate? I had the impression that this number was just used to
> configure
> system generator to apply the correct timing constraint. I
previously only
> used the ADC clock in which case that would make sense, but it never
> occurred to me that it could also configure the DCM. I will give
it a try.
> Thanks again,
> Glenn
>
> On 12/11/07, Oren Milgrome < o...@berkeley.edu
<mailto:o...@berkeley.edu> > wrote:
>>
>> Hi, double click on the yellow "XSG Core Config" block to set
the clock
>> options for the BEE2 and IBOB's. Hope that helps...
>>
>> > Hi,
>> > Is it possible to set the user clock to arbitrary frequencies
using
>> > the DCM without venturing too far from the CASPER tool flow? Any
>> > examples would be appreciated, either for the BEE2 or iBOB
>> > Thanks,
>> > Glenn
>> >
>> >
>>
>>
>> --
>> Oren Milgrome
>> University of California - Berkeley
>> Radio Astronomy Lab 601 Campbell Hall
>> Berkeley, CA 94720-3411
>> mobile: 510 368 6857 office: 510 642 5509
>> lab: 510 642 0381 fax: 510 642 3411
>> email: o...@berkeley.edu <mailto:o...@berkeley.edu>
>>
>>
>
--
Oren Milgrome
University of California - Berkeley
Radio Astronomy Lab 601 Campbell Hall
Berkeley, CA 94720-3411
mobile: 510 368 6857 office: 510 642 5509
lab: 510 642 0381 fax: 510 642 3411
email: o...@berkeley.edu <mailto:o...@berkeley.edu>
