DATA packets timestamp with the raw value of the producer's high-resolution
counter, and the wire never said how fast that counter runs. The hub divided by
its own timer's frequency instead, which is only the same number while producer
and hub share a machine — on x86 it is the TSC frequency and differs from model
to model. Off-box, every accumulated batch was therefore laid out over the wrong
span of time: the samples in it drift away from where they belong and start
colliding with the next packet's, which is the "same" symptom as a stale time
base even though nothing is out of order.
CONFIG now carries the rate as a trailing uint64, alongside the publish-mode
byte and read the same tolerant way: absent or zero means the producer did not
say, and the hub falls back to its own timer as before. Anything below 1 kHz is
not a high-resolution timer and is refused, so a mis-parsed payload cannot
stretch a millisecond batch across seconds.
The Accumulate DATA payload is unchanged, so this costs nothing per packet and
the period *within* a batch is still estimated from the gap between packets.
The Go, C and browser parsers already ignore trailer bytes they do not know,
so they read the new CONFIG unchanged; none of them uses the HRT timestamp.
Also corrects the Accumulate DATA layout in all three protocol documents: they
described it as one snapshot per array signal, where it has always been one per
accumulated cycle.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
