Bob kb8tq writes:
> Could be. They also mention a 25 MHz clock on the card. That could
> get you to a 125 MHz time base with a 8 ns resolution. Again, without
> a deep dive into what they did - who knows.
That is the clock-supply to the 82599 chip, but there is a boatload
of PLL'ery
Hi
> On Jul 4, 2022, at 10:04 AM, Poul-Henning Kamp via time-nuts
> wrote:
>
>
> Poul-Henning Kamp via time-nuts writes:
>
>> The timestamping counter gets its clock from the ethernet line
>> signals, and the counting frequency therefore depends on the ethernet
>> speed:
>>
>>
Poul-Henning Kamp via time-nuts writes:
> The timestamping counter gets its clock from the ethernet line
> signals, and the counting frequency therefore depends on the ethernet
> speed:
>
> 100 Mb/s1.5625 MHz
> 1 Gb/s 15.625 MHz
> 10 Gb/s 156.25
John Miller via time-nuts writes:
> I'm curious if anyone here knows much about these silicom timestamping
> network interfaces?
I used the i82599 ethernet chip ten years ago, to measure time in
the first Adaptive Optics Real-Time Computer prototype we built for
ESO's ELT telescope.
I
Hi
I think the key parameter is the 8 ns resolution on the time stamp.
That may or may not be adequate for this or that application.
Without doing a deep dive on the part, it’s not real clear how they
deal with the accuracy of the onboard timebase. It’s rated at 0.01 ppm
with no real details.
