Re: [casper] QDR ROACH2: clocking at 145 MHz

[Jack Hickish]

Hi JP,

What mlib_devel are you using? Did you actually build against commit
72d879c? I noticed you emailed a link to my repository which I specifically
tweaked for my higher (312MHz) work, which I'm sure breaks *everything* at
145.

Cheers,
Jack

On Fri, 22 May 2015 at 06:41 Juan-Pierre Jansen van Rensburg <
jvrensburg...@gmail.com> wrote:

> Hi all,
>
> I'm trying to get the QDR on the ROACH-2 to work reliably at a clock speed
> of a 145 MHz. I'm assuming this is possible, since it has been pointed out
> in an earlier message
> 
> that the QDR should work above 120 MHz?
>
> I'm running the software calibration for the QDR (qdr_cal() in the qdr.py
> script) and the calibration seems to be successful, however after the
> calibration I write test patterns to the QDR but the data I read back is
> incorrect. What is  strange is that it doesn't do it for all the test
> patterns, mainly for the walking 0's and pseudo random numbers, and QDR0
> and QDR1 seem to be the main culprits for failure. I also don't have any
> QDR glitches at higher clock speeds (for instance at 200 MHz).
>
> I have been digging around and found this
>  possible
> solution (see commit 72d879c). The REFCLK for the IDELATCTRL is set to a
> 100 MHz instead of the recommended 200 MHz. I have tried this, but I still
> get errors. I'm not sure if this is relevant but with this suggestion I
> have only found errors so far on QDR1?
>
> Does anyone have any suggestions?
>
> Thanks,
> JP van Rensburg
>
>

[casper] QDR ROACH2: clocking at 145 MHz

[Juan-Pierre Jansen van Rensburg]

Hi all,

I'm trying to get the QDR on the ROACH-2 to work reliably at a clock speed
of a 145 MHz. I'm assuming this is possible, since it has been pointed out
in an earlier message

that the QDR should work above 120 MHz?

I'm running the software calibration for the QDR (qdr_cal() in the qdr.py
script) and the calibration seems to be successful, however after the
calibration I write test patterns to the QDR but the data I read back is
incorrect. What is  strange is that it doesn't do it for all the test
patterns, mainly for the walking 0's and pseudo random numbers, and QDR0
and QDR1 seem to be the main culprits for failure. I also don't have any
QDR glitches at higher clock speeds (for instance at 200 MHz).

I have been digging around and found this
 possible
solution (see commit 72d879c). The REFCLK for the IDELATCTRL is set to a
100 MHz instead of the recommended 200 MHz. I have tried this, but I still
get errors. I'm not sure if this is relevant but with this suggestion I
have only found errors so far on QDR1?

Does anyone have any suggestions?

Thanks,
JP van Rensburg