ZephCore 1.16.8-zephcore

A power and radio-measurement release. Repeaters no longer wake on a fixed 5 s tick — they sleep
until their next real deadline. Every ESP32 build drops to 80 MHz, and Heltec repeaters now light-sleep
between packets. The noise-floor sampler and CAD probe were unified into one measurement, the
SX126x RSSI/AGC calibration is now band-correct, and the observer role got a batch of fixes for settings
that silently never reached the hardware.

Highlights

Repeaters are now deadline-driven — the periodic housekeeping tick is gone

Every repeater woke five times a second-and-a-bit forever: a fixed 5 s "housekeeping" timer that ran the
noise-floor sample, the CAD probe, advert timers and the tempradio revert. None of that actually needs a
poll — each item is either a deadline or a sampler with its own interval.

The new mesh/Maintenance.h contract lets the event loop ask "when does maintenance next have work?"
and arm one one-shot wake for exactly that moment. An idle repeater now sleeps until its soonest real
deadline instead of on a fixed cadence. A hard ceiling (CONFIG_ZEPHCORE_MAINTENANCE_BACKSTOP_MS,
default 60 s) clamps the wake as a safety net against a missed deadline — it should never bind in
normal operation.

Companions and room servers keep their periodic tick deliberately: the companion block contains genuine
pollers (contact-dump progress, BLE advertising watchdog) with no deadline to arm, and the room server is
paced by its own 500 ms push timer regardless.

ESP32 power: 80 MHz everywhere, and light sleep on Heltec repeaters

Espressif parts have no equivalent of the nRF52's "idle at microamps in WFI" — WAITI gates the core
clock but leaves PLL, peripherals and RAM powered, so an idle ESP32 sits in the tens of mA. CPU
frequency is therefore a first-order term in a battery node's draw, and light sleep (sub-mA) is what
removes the rest.

• Every ESP32 build is now pulled to 80 MHz, matching what Arduino MeshCore ships (new
  hal-espressif patch 0002 — upstream omits 80 from its DT map). Observers are the exception and
  keep the SoC maximum (240 MHz on S3/classic, 160 MHz on C3/C6): they run a full WiFi + TLS + MQTT
  stack and are mains- or big-panel powered, so throughput matters more than current.
• Light sleep is now enabled automatically for repeater builds on Heltec V3, V4, V4.3,
  Wireless Tracker and Wireless Tracker V2. Patch 0012 marks the LoRa DIO1 line as a wakeup source,
  so a received packet wakes the SoC — the node sleeps between packets and deadlines and wakes for real
  work. Combined with the deadline-driven change above, an idle repeater now spends most of its life
  asleep instead of waking five times a second at 240 MHz.

Console output itself is safe: a new pm_notifier flushes the console UART to idle before every sleep,
which Zephyr's PM path does not do — without it, lines would be cut mid-character. Packet-logging and
debug builds are therefore fine to run with sleep enabled.

Anything that can't tolerate sleeping holds a pm_policy lock instead of being excluded by hand: a
WiFi OTA session holds one for its duration, an uplink/observer WiFi station holds one
permanently (the association would drop), and GPS holds one while the module is powered, since the
GNSS UART is not a wake source and inbound NMEA would be lost. Under a GPS duty cycle the lock is only
held during the awake phase.

One measurement now serves both the noise floor and CAD — set probe.interval

The noise-floor sampler and the CAD calibration probe used to be two separate things riding the same
5 s tick. They are now a single periodic radio measurement: one median-of-8 RSSI reading that the
CAD probe consumes rather than measuring again.

• set cad.probe.interval <sec> → set probe.interval <sec> (default still 15, 0 still
  disables CAD probing). It is now also the noise-floor sampling rate, and it sets how often an idle
  repeater wakes.
• New CONFIG_ZEPHCORE_NOISE_FLOOR_INTERVAL_MS is the build-time fallback used when probing is off —
  15 s on repeaters, 5 s on companions/room servers (which wake on their tick anyway).
• A sample blocked by TX, mid-RX or a duty-cycle sleep window retries on a 5 s deadline (max 2 retries)
  instead of losing a full interval — deliberately reproducing the old retry grid, which matters under
  RX duty cycle where blocked attempts are the norm.

RSSI reads are now correctly spaced. A median only rejects outliers if the reads are independent,
and the chip refreshes RSSI once per averaging window (~16 µs at BW 62.5, ~134 µs at BW 7.8) — reads
issued faster return the same underlying sample and the median collapses to a single read. The spacing
and the RX-entry settle delay are now derived from the SX1261/2 datasheet (rev 2.2, Table 13-82).

get cad reports the result so the assumption stays falsifiable on real hardware: the old iv: field is
replaced by sp:<mean-spread>/<zero-spread %>(<count>). A non-zero mean proves the reads are
independent, however high the zero-spread share climbs — only mean 0.0 with a high share indicts the
sampler. Measured on air at BW 62.5: 0.6/90% quiet, 0.9/84% with the floor at −103 dBm.

Fixed: SX126x RSSI/AGC calibration used the wrong band on sub-GHz builds

Datasheet rev 2.2 (§6.1.6, new in Dec 2024) documents that the SX126x RSSI/AGC calibration registers are
band-specific. ZephCore applied the 868–915 MHz set unconditionally, so every 433 MHz build was
running the wrong AGC gain selection — that is packet loss, not just wrong telemetry. New patch
0011 adds the per-band table plus the shared-register 0x08AC / AgcSensiAdjust fix.

RAK3401 1-watt: external-PA RX register patch enabled

The undocumented register 0x8B5 RX improvement (CONFIG_ZEPHCORE_SX126X_HELTEC_REG_PATCH) is not
Heltec-specific despite its name — upstream MeshCore also enables it for the RAK3401's SKY66122 FEM. It
is now on for rak3401_1watt, and the Kconfig help was corrected to say "boards with an external PA/FEM
in the RX path."

The AGC-reset workaround is gone

set/get agc.reset.interval has been removed — it now replies use rxduty instead, and set is
accepted-and-ignored for prefs compatibility. It was a periodic blind AGC kick that only existed because
of the fixed tick; the in-driver RX restore and duty-cycle re-arm paths handle the real cases.

Observer role fixes

Several observer settings looked accepted and then never reached the hardware:

• set freq/sf/bw/cr never reached the radio. The radio was bound to a static placeholder
  NodePrefs that is never loaded from flash, so it stayed on compiled-in defaults forever — the value
  was written to flash and echoed back by the CLI and MQTT, then "reverted" on reboot. The radio is now
  bound to the mesh's live prefs before begin(), matching repeater and room server.
• First boot discarded the observer defaults. The store is shared with the repeater, and its no-file
  branch re-applies repeater defaults over whatever the caller passed in. The observer now detects
  first boot itself and re-applies (and persists) its own cr / tx_power once.
• set name Observer reverted on every reboot — "Observer" was in the regenerate-if-unset list. It
  is a name a user can legitimately set, so it is no longer treated as unset.
• set freq / set bw now refuse values the loader will reject (300–1000 MHz, 7–500 kHz). Out-of-
  range values used to save fine, then get silently reset to defaults on the next boot — taking
  bw/sf/cr/tx_power with them.
• USB-console routing fixed on Station G2 and XIAO ESP32-S3, so non-companion roles keep their
  console and serial CLI.
• The observer help banner was reorganised (network / node / radio / query) and now lists the query
  commands that already existed.

Upstream sync

Synced with Arduino MeshCore dev:

• Room server: room.post <message> — post to the shared room as the server itself. Pushed to
  clients like any other post.
• Fixed: an empty guest password granted read+write to anyone. An unset guest.password (the
  default) now disables guest login instead of matching an empty submitted password. To run an open
  room server use set allow.read.only on, which grants read-only. Both password compares still run
  unconditionally, so timing behaviour is unchanged.
• Companion telemetry: MCU die temperature is now reported under base permission, matching Arduino
  MeshCore and ZephCore's own repeater/room-server telemetry. It is still suppressed when an external
  sensor already supplied a temperature, so a node never emits two.
• Advert names are truncated on a UTF-8 code-point boundary — a name whose multi-byte character
  straddled the advert size limit used to go out mangled.
• ThinkNode M3: GPS reset pin left floating. Driving the REINIT pin (P0.25) stops the module
  producing NMEA on this hardware; upstream fixed it by never driving it. The gps-reset alias is gone,
  which compiles out every reset path — GPS_EN alone handles wake/standby.
• New patch 0013 bounds the SX126x RX-busy latch with a payload deadline. Continuous RX has no
  symbol timer, so a HEADER_VALID whose packet never completes would pin the TX gate open forever and
  silently mute the node. The bound is max-length airtime at the current SF/BW +25% +100 ms —
  deliberately generous, a stuck-state safety net rather than a timing mechanism.

Other changes

• west manifest bumped (routine pinned-tree advance).
• ARCHITECTURE.md, ADAPTIVE_CAD.md and Repeater_CLI_commands.md updated for the probe unification
  and the removed commands.

Recommended upgrade checklist

1. Heltec V3 / V4 / V4.3 / Wireless Tracker repeater? You get 80 MHz and light sleep
   automatically. Do your configuration in the first 10 minutes after boot, or reconnect your terminal
   (which resets the node) to get the window back.
2. Running a 433 MHz SX126x node? Update — the RSSI/AGC calibration band fix affects reception, not
   just readings.
3. Running an observer? Update, then re-apply your radio settings once — they may never have reached
   the hardware before.
4. Scripts or notes using cad.probe.interval / agc.reset.interval? Update them to
   probe.interval; the AGC command is gone.
5. ESP32-S3 / ESP32-C boards that skipped v1.16.5: flash -merged.bin once over USB/serial. Data survives.
6. Everything else, from v1.16.2 onward: just flash — bonds and data survive.
7. From v1.16.1 or older: just flash — self-migrates on first boot; re-bond once.
8. From Official MeshCore: just flash — auto-formats on first boot.
9. Anything odd? Format first.