Power-saving diagnostics

Use set powersaving.diag on to collect the real sleep-policy decisions in RAM, and get powersaving.diag to inspect them. This is available in Companion, Repeater, Room Server and Sensor, without a separate diagnostic build. It does not override any sleep guard. The production USB/DTR policy is unchanged.

Suggested test

Record get powersaving, radio/RXPS settings, logging and bridge settings.
Run set powersaving.diag on, then close the USB terminal for the test.
Let the node run long enough to cover noise-floor calibration, queue work and scheduled tasks; a one-second snapshot can be misleading.
Reconnect and run set powersaving.diag off promptly to freeze the window.
Read get powersaving.diag, get powersaving.diag calls, get powersaving.diag time and pages 3 through 8.
If necessary, clear and repeat with only one feature changed.

Reconnecting/reading creates real USB or serial work and can affect the final decision and counters. Prefer accumulated time over that final why value; check its age. Off freezes recorded values, not the node itself. Re-enabling after off starts a fresh window. Collection defaults off at every boot.

Interpreting the result

policy.off: the saved policy does not permit MCU sleep.
usb.session: an actual host session or board-specific host/grace guard, not merely USB power from a charger.
usb.logging: an existing logging guard (not a blanket nRF52 veto).
usb.recovery: USB recovery/watchdog work needs service.
bridge, bridge.cleanup, bridge.wake: active UART/network bridge, shutdown work or an overdue standby wake. A suspended RS232 owner is not diagnosed as running just because its saved enabled flag is on.
calibration: noise-floor work is due now. The CPU can idle between sample deadlines even while the radio remains in continuous RX for calibration.
radio.watchdog: radio observation/recovery work.
queue, retry, scheduled, mesh, ota, radio2: pending role work.
wireless, network, serial, button, tracker, morse: a matching existing service guard is active.
board, no.wake: an inner board veto, SDK error or lack of a wake source.

radio2 means the scanner cannot safely idle right now: for example, a short remaining visit, calibration, pending reception or an unvalidated platform. On nRF52, settled long visits can idle the MCU with power saving enabled; the RF receiver stays on. See radio profiles.

The role reports the first actual short-circuit blocker. It does not query otherwise skipped hardware just to populate an exhaustive list. Board guards may add reasons. Per-reason durations therefore are observed guard time, not the independent energy cost of each feature. The state page's blocked time is the union; adding per-reason totals can double-count overlap.

calls and time instrument actual nRF52 event waits, ESP32 manual light sleep and generic RP2040/STM32 WFI paths. ESP32 automatic power-management yields are not direct wait calls. A return under 100 us is counted as short; it can be a legitimate pending interrupt/event, not an SDK failure. SDK errors have their own counter and detail. Time inside the wait includes interrupt/SDK overhead; it is not measured sleep residency. USB debugging/SWD can alter power and clock behavior, so compare like-for-like setups.

These are not current measurements. Radio continuous RX, RXPS parameters, FEM/LNA gain, GPS, displays and board regulators can explain large current differences even with good MCU sleep. Use a current meter and matched settings to attribute those loads. Counters are RAM-only, saturating, and consume at most 256 bytes of collector state. Each wait-call interval must be shorter than the 32-bit micros() wrap (about 71 minutes); the normal wait paths here are much shorter. Keep gaps between policy observations below the millis() wrap (about 49 days).

Noise-floor sampling and sleep

Startup still collects a complete baseline promptly: 64 accepted samples, at least 50 ms apart, after the radio frontend has settled. Collection keeps the radio in continuous RX when needed, but the CPU may sleep between reads. Pending packet interrupts retain their normal receive owner. Rejected readings retry at 50 ms intervals, and the existing 30-second collection timeout bounds an attempt on a busy channel.

After a successful baseline, ordinary single-profile refresh waits five minutes. A rejected rise or failed attempt retains the last usable floor and retries after one minute. Gain/tuning changes and radio recovery still request immediate recalibration. Adaptive AGC maintenance with an unchanged RF path retains a valid baseline and its existing refresh deadline; it does not cancel a pending collection or postpone a failed-sample retry. Legacy fixed-cadence AGC resets still request recalibration. Dual-profile scanning keeps its existing timing and calibration policy.

ESP32 timed sleep uses a millisecond timer capped at the next sample deadline. Repeater, Room and Sensor also preserve millisecond queue, retry, RS232 standby, scheduled-radio and maintenance deadlines, so the last fraction of a second does not become a busy-wait tail. A future sub-second deadline is not reported as blocked work; a deadline that is already due still prevents sleep. nRF52, RP2040 and STM32 retain their interrupt-idle wake paths. Other sleep guards, including USB/logging, packet queues and bridges, still apply. These changes have host scheduling tests and firmware build coverage; their power benefit requires a new matched hardware/current measurement.

See the CLI reference for all page names and commands.

The nRF52 idle-sleep investigation describes an eligible-but-not-sleeping regression, its fix, controlled hardware evidence and the limits of CPU-state sampling without a current meter.

Board regulator initialization

RAK4631 Companion uses the same nRF52840 REG1 DC/DC initialization as the other RAK4631 roles. The former Companion-only force-LDO flag has been removed. This does not change REG0, the SX1262 regulator, storage layout, or boot-voltage protection. The shared initializer uses the SoftDevice API when BLE's stack is already active and the hardware register otherwise; Companion starts the board before it starts Bluetooth.

RAK documents DC/DC support for the module. The related upstream battery-startup report #1878 concerned Repeater firmware, with BLE Companion reported working on an affected board. It did not establish filesystem corruption or a Companion-specific DC/DC failure. PR #1914 also changes boot-voltage/wakeup handling and is not proof that every failure in that thread has the same cause.

Host startup tests cover both SoftDevice states and regulator selection before the boot-voltage check. Firmware compilation is not hardware qualification: compare battery-only cold starts, low-voltage recovery, BLE operation and settings writes/reboots on the actual board/baseboard revisions before a fleet rollout. USB power can mask the reported startup symptoms. A current meter is still needed to quantify the power difference.

The following boards also now call their declared NRF52BoardDCDC initializer instead of bypassing it with NRF52Board::begin(). This applies to every role that uses the board class, not just Companion, and does not require enabling the runtime sleep policy. The nRF52840 hardware manages the enabled regulator according to load. This is REG1 only, not a blanket change to REG0 or an external LDO, PMIC output, or radio regulator.

Board	Circuit evidence used for REG1 support
Heltec T1	T1 V1.0 schematic, DCC-to-DEC4 inductors and capacitors.
Heltec MeshPocket	MeshPocket schematic, DCC-to-DEC4 L1/L2 and C5/C6.
Heltec MeshSolar and MeshTower V2	HT-N5262M module circuit, L1/L2 and C1/C2. Heltec links this circuit from its MeshTower V2 resources; MeshSolar's datasheet identifies the module.
LilyGO T-Echo	T-Echo schematic, REG1 DC/DC network and explicit DC/DC-enabled design note.
Ikoka Handheld, Nano and Stick nRF52	XIAO nRF52840 circuit, DCC L1 and DEC4 capacitors. The designers identify XIAO as the MCU for Handheld, Nano and Stick.
Minew ME25LS01	Manufacturer datasheet, electrical schematic page 9: MCU DCC through ML2/ML3 to DEC4_6 and MC15/MC16.

The startup tests execute each real begin() with SoftDevice off/on and power management compiled out/in. They require DC/DC before peripheral initialization and before any enabled boot-voltage check, while retaining one common board initialization. The previous bypass fails these tests.

ThinkNode M3/M4/M6 and generic ProMicro remain unchanged pending exact circuit or physical-board confirmation; their DC/DC inheritance alone is not evidence. Nano G2 Ultra, ThinkNode M1/M8 and Keepteen LT1 retain their plain NRF52Board initializers for the same reason. The MeshTracker X1's LR2021 regulator likewise remains unchanged. Do not turn on a switching regulator without its required inductor/capacitor network. The MCU and LoRa regulator choices are independent.

Meshnology W12 transmit preparation

The W12 adopts the GC1109 TX preparation from upstream PR #3579, but keeps the PA shut down in ordinary standby rather than permanently selecting TX mode. Before sub-GHz packet or Morse CW transmission, it temporarily enables the LF PA in standby, waits 1 ms, starts TX, then restores the normal standby mask. The TX mask stays unchanged during that restoration. Failure paths restore all affected DIOs and request radio recovery if the PA state cannot be confirmed. The 2.4 GHz path and other LR2021 boards do not use this LF prearm policy.

LF/HF FEM rail changes now settle for 1 ms instead of 100 ms. Packet-wake deep sleep retains only the selected FEM rail; terminal shutdown retains both rails off. This is separate from the W12's existing circuit-verified DC/DC setting.

Native fault-injection tests cover the mask transitions and power retention; RF envelope and battery-current measurements on a physical W12 are still needed to validate the TX improvement and quantify power use.