--scan's walk was unwalkable on POSIX: probe rates have no termios
B-constant, so the first off-nominal probe raised out of the loop. The port
speaks termios2 BOTHER now (red-proven on a pty at 9984 Bd), the probe's
open lives inside the walk's error handling, an fd no longer leaks on an
unmakeable rate, and the swallowed unknown-signature reply is named at
timeout instead of reported as silence. CMakePresets.json's generator emits
the submodule toolchain path it had drifted from — a hand edit on a
generated file, exactly the class rule 10 exists for — and presets.generated
gates the pair from here on (the marker CMake rejects at the
presets root stayed out; the check is the guard). The over-slot image guard
the tsb runner gained reaches the pureboot runner too; the GPIO bridge's
delivery comment states the hardware truth (RXC at the stop bit's sampling
point); the hardware suite gains the scan check — the one place the rate
physics is real; and the libavr pin advances over both audit rounds.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The RC-oscillator answer's host half. --scan probes ±10 % around the built
rate in 2 % steps, nearest first, one activation window (one reset) per
probe: a fixed-baud loader whose oscillator drifted answers at the ratio,
and the report gives the session workaround (--baud), the offset, the
OSCCAL direction at ~1 %/step, and the autobaud way out. The walk and the
advice are logic-tested (test_scan.py, red-proven on the trim direction) —
a pty carries bytes at any rate, so the wire cannot arbitrate them.
On an autobaud session --info now reads the measured bit period from
ram_start — the geometry table gains that column — and undoes the unit's
encoding ((cycles − 8) / 4, floored: libavr's spin granule and per-bit
overhead), so the printed clock is the true one within a granule; --clock
turns it into a stated drift. The autobaud end-to-end asserts the figure
inside exactly that envelope at both clock points.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
