PPS over USB

[James Browning]

James Browning first wrote:
JB> I haven't tested it yet, as I'm attempting to 'improve'
JB> my PPS over USB setup.

To which Hal Murray replied:
HM> Do you know what you are getting into? 1/2 ;)

No, not a clue. It looked like a fun aside
while my merge requests ferment.

I do not recall having seen those graphs before.

I looked up the Host Controller Interfaces: they are
Universal (1.x Intel/Via), Open (1.x everyone else?),
Enhanced (2.x), and eXtensible (3.x).

Later, Dave Hart chipped in:
DH> It would really help if someone would introduce a USB 3 UART.

I do not think it profits the vendors enough, yet.

---

The notion I had was to measure the greatest and the least host
offsets in microseconds. Also, stash the number of samples before
a 900 (or more) microseconds drop.

Take the midpoint of the range(?) and store it to be added to the
next batch of samples.

Then, take about a third of the slope from the notional bottom
left to the top right and subtract it from the above results.

I think it worked better before I ported it to C.