[time-nuts] an interesting problem

[jimlux]

On 2/6/11 12:37 AM, cook michael wrote:
> I had a quick look at the IEEE-1355 HIC bus on which spacewire is based
> and it seems that although the clock is not on the wire, it can be
> reconstructed as an XOR of the strobe and data. So a passthrough
> connector sampling those lines (differential) with RS-644 receivers and
> a quad NAND may be all you need to recover it.
>



Oh.. that's a clever approach.. the signals "on the wire" are derived 
from the same oscillator.

The problem is that the signals aren't there all the time (while the 
clock is recovered from XORing D and S, there aren't always bits on the 
wire.  You can have idle time of up to 850ns.

One could do a similar thing to measure the properties of the oscillator 
on an Ethernet system.