DigiRadio/Software/docs/TODO.md

TODO — DigiRadio firmware

Agent task list and hardware-in-the-loop backlog. Working directory for all commands is Software/.

Current firmware: 0.9.0 — everything in 0.8.5, plus: Si4684 RF blackout root-caused and fixed (real FM/DAB lock and audio on real hardware), DAB service list fixed (two rounds), FM ANTCAP antenna calibration persisted to EEPROM, generic ADAU1701 parameter API, phone PCM streaming, BLE Wi-Fi provisioning, full FM band scan, BT1035 boot retry. See "Post-0.8.5 hardware-in-the-loop findings" below and docs/si4684-rf-investigation-report.md for the full story.

Before writing code, read AGENTS.md, .cursor/rules/, and instructions.md. Definition of Done: Apache header, doc blocks, doxygen Doxyfile exits 0, host tests pass, check-manual-sync.py and check_si4684_blobs.py pass, no plaintext secrets.

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Completed agent tasks (T1–T12, fw 0.7.1–0.8.5)

Task	Version	Summary
T1	0.7.1	Doxygen warnings cleared
T2	0.7.1	CI workflow (host tests, Doxygen, manual sync)
T3	0.7.2	Preset reorder API/UI, DAB playing ids in status
T4	0.8.0	RDS/DLS broadcast metadata
T5	0.8.1	IntegrationService — startup, preset recall, last-preset NVS
T6	0.8.2	Tabbed configuration Web UI (REST coverage)
T7	0.8.2	Si4684 blob policy — gitignore, docs, check_si4684_blobs.py
T8	0.8.3	NVS + flash encryption — initEncryptedStorage, security docs
T9	0.8.4	Dual-OTA partition table + dsp blob slot, rollback Kconfig
T10	0.8.4	EEPROM EUI-48 identity — SoftAP/BT/hostname/serial
T11	0.8.4	Updatable ADAU1701 program — POST /api/dsp/program, DRAD blob
T12	0.8.4	ESP32 OTA — POST /api/system/ota, rollback confirm on boot

0.8.5 (hardware/doc alignment): BT1035 boot uses AT+AUXCFG=3 + AT+I2SCFG=67 (I2S from ADAU1701, not Line-In); I2C pull-ups R1/R16 confirmed 2,kΩ; Hardware/DATASHEET/ bundle + manual cross-refs.

Also landed (not numbered): BT1035 pairing (BluetoothService), station presets (fw 0.7.0), companion-chip boot (Slice 3), ADAU1701 runtime (Slice 5).

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P4 — Hardware-in-the-loop (when PCB arrives)

Manual validation only — does not block host CI.

H1. Encrypted NVS boot path

Follow docs/security-flash-nvs.md: first flash with idf.py erase-flash flash, verify boot logs, Wi-Fi provisioning survives reboot, presets and last_preset survive power cycle.

H2. End-to-end listening

Si4684 DAB/FM tune, ADAU1701 profile apply, BT1035 A2DP to headphones, now-playing metadata in UI and /api/tuner/status.

H3. OTA and DSP program update (on hardware)

Push a known-good .bin via POST /api/system/ota, confirm rollback after a deliberately bad image. Upload a DRAD blob via POST /api/dsp/program and verify ADAU replay after reboot.

H4. Production flash encryption (optional)

After H1 passes, trial build with sdkconfig.defaults.production overlay on a sacrificial unit; confirm RELEASE mode policy before shipping.

H5. Si4684 FM/DAB no-lock — RESOLVED, was firmware after all

Superseded verdict (2026-08-13): blob OK → suspected U6 RF ground, PCBWay dispute opened. That verdict was wrong. The actual cause was writeCommand()'s ARG1 byte being mis-offset across FM/DAB tune, seek, and several status/ack commands — the chip always answered correctly, so every signal pointed at hardware, but it never actually tuned. Fixed; real FM lock, real DAB ensemble lock, real audio confirmed live on the same board. No PCB rework was needed. Full investigation, the wrong initial verdict, and the eventual root cause: docs/si4684-rf-investigation-report.md.

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Post-0.8.5 hardware-in-the-loop findings

The board arrived and testing against it (not just host tests) found real bugs the host-testable core couldn't catch, since they live in ESP-IDF-only drivers. Full detail and evidence in docs/si4684-rf-investigation-report.md. Short version:

• Si4684 total RF blackout (H5 above) — firmware bug, fixed.
• Si4684→ADAU1701 digital audio silence — PIN_CONFIG_ENABLE mutual exclusion + SerialInputRegister polarity, fixed.
• DAB service list empty/garbled — response-parsing offset bugs (two rounds) plus DAB_EVENT_INTERRUPT_SOURCE (0xB300) never configured, fixed.
• FM front-end auto-tune measurably suboptimal on this board's actual matching network — ANTCAP calibration swept and persisted to EEPROM, POST /api/tuner/calibrate-antenna.
• BT1035 total boot silence — root cause found and fixed (2026-08-20): the module's spontaneous boot banner (+VER=..., +DEVSTAT=1) doesn't appear until ~18-24s after RESET# releases (full BT stack init, not just the internal regulator), but the boot code only waited 3.5s before cutting power and restarting — so every attempt, in every prior session, cut power before the module could ever finish booting even once. Power rails (VBAT_IN/SYS_CTRL/VDD_IO/1.8V_OUT) and TX/RX wiring were all independently verified correct with a multimeter first — the module and PCB were never at fault. Fixed by waiting up to 25s for the banner (kBootBannerWaitMs); boot now succeeds on the first attempt.
• BT1035 — a second, harder failure mode confirmed intermittent, not hardware (2026-08-21). Distinct from the banner-timing bug above: even with the 25s wait already in place, boot sometimes still gets zero UART bytes at all — no banner, no AT response, silent across all 8 probed baud rates (9600-921600). Root-cause evidence this session: VBAT_IN (3.3V), 1.8V_OUT (1.8V), SYS_CTRL/RESET (~3.27V, matching the firmware's own GPIO readback), and BT1035 TX (idle-HIGH ~3.29V, no short/float) all measured normal with a multimeter. The BT1035's 32 MHz crystal is integrated inside the sealed Feasycom module (confirmed via the module's own datasheet block diagram — no external crystal on our schematic), so it can't be inspected or reworked from our side; a marginal oscillator-startup margin inside the module is the leading suspect. Decisive evidence it's intermittent, not a dead unit: the exact same physical module booted cleanly (banner + all AT commands OK) on one attempt and went totally silent on the very next attempt, no physical changes in between. A replacement module is therefore not a guaranteed fix — the same defect class could recur on a different unit. Mitigated (not fixed) by an indefinite background retry task (hardware::bt1035RetryTask in main/hardware_bootstrap.cpp): if the initial Bt1035Driver::boot() fails, a background FreeRTOS task keeps calling boot() again with no artificial delay between attempts (each attempt already takes ~25-60s on its own) until it succeeds, while the rest of the system (tuner, Wi-Fi, web UI) stays fully usable in the meantime. Turns a permanent-until-manual-power-cycle failure into a bounded, self-recovering delay. See docs/si4684-rf-investigation-report.md (2026-08-21 entry) for the full session narrative, including a UART TX/RX loopback test attempt that was inconclusive (bridging the ESP32's own TX/RX pins from cold boot caused an unrelated, reproducible, harmless early-boot hang, not yet explained).
• BT1035 — git archaeology + minimal patch, follow-up (2026-08-21). Traced the full commit history of Bt1035Driver.cpp from the last documented-good boot (6ca40f1) through the regression (6f7b6dd, a redundant AT+RESET) and its fix (fd9d4ae, 5/5 clean boots — removed the AT+RESET and introduced the boot-banner listen at 3500ms in the same commit). Comparing fd9d4ae to this session's working tree found one real structural difference beyond the justified 25s banner window: today's earlier commit (3a58d33) had added an intra-boot() retry loop (2 attempts, only 300ms between hardware reset pulses) that never existed in the validated baseline — shorter than the BT1035 datasheet's own "Reset Protection timeout (typically >1.8s)", so the second pulse may not have reached a clean power-off state. Fixed: removed the intra-boot() retry loop entirely (kBootAttempts/kBootRetryDelayMs deleted); boot() now makes exactly one attempt per call, matching fd9d4ae. Retries remain exclusively at the bt1035RetryTask level (whole clean boot() calls, never re-pulsing pins faster than one full cycle apart — confirmed live, ~31.8s between attempts). Host tests (20/20) and firmware build green; flashed and observed live. Result inconclusive on hit rate: a 20-minute post-flash window captured 31 consecutive silent retry attempts, zero successes — worse than earlier the same day. The patch is kept because it's structurally correct (only known deviation from the historically validated design removed), not because this sample proved a better success rate. Root cause of the underlying intermittent silence is still open (see entry above).
• BT1035 — RESET#/SYS_CTRL redesign, CTS/RTS diagnostics, Feasycom escalation (2026-08-22). A sibling project's PinScope netlist report (RESET# pulled to GND, SYS_CTRL pulled HIGH by stray resistors) was checked against our own schematic and does not apply to us — our RESET#/SYS_CTRL wiring is correct, verified via netlist. Its RF_OUT/pin 51 floating finding does also apply to us, but is a separate, RF-range-only concern (datasheet documents both internal- and external-antenna variants; can't tell which we have), not the cause of the digital/UART boot silence. As a diagnostic test, RESET# is now never driven at all (floating input, relying on the module's own internal pull-up per §4.8) and SYS_CTRL now does a genuine LOW(2.5s)→ HIGH power-cycle on every retry attempt (previously asserted once ever and left alone, meaning retries never actually power-cycled the module). Also added read-only diagnostics on the previously-unused CTS/RTS pins (physically wired, named in board_pins.hpp, never configured by any driver code, host flow control disabled) — live readings were perfectly stable (CTS=HIGH, RTS=LOW) across ~12 samples over 30+ minutes, arguing against pure floating-noise. Across all of today's changes combined, zero successful boots were observed in cumulative 45+ minutes of live testing — inconclusive-to-negative, not proof any change helped or hurt. Escalated to Feasycom support with a detailed email (drafted, kept outside the repo) covering the symptom, everything ruled out, the CTS/RTS open question, and the antenna-variant question; paused further live experimentation pending their reply rather than keep permuting timing parameters blind.
• Still open: intermittent multi-second HTTP unresponsiveness under load; DAB signal quality still antenna-limited; 24 KB nvs partition may be undersized (saveProfile() store_failed seen intermittently, error code never captured); BT1035 intermittent total-silence boot failures (mitigated via background retry, not root-caused — see above).

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Open firmware polish (non-blocking)

Done in fw 0.8.5 unless noted:

• BT1035 boot — I2S slave init (AT+AUXCFG=3, AT+I2SCFG=67) per PCB routing (0.8.5).
• FM seek down — POST /api/tuner/seek with {"direction":"down"} (0.8.4).
• BT1035 — query/set name, paired list (AT+PLIST), auto-reconnect (AT+AUTOCONN) per Feasycom BT1035 manual (0.8.4).
• Si4684 — STOP_DIGITAL_SERVICE (0x82) before FM band switch when DAB audio is active; ensemble metrics remain via DAB_DIGRAD_STATUS in status (0.8.4).

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TODO — calibration functions need to become permanent, in-firmware, on-demand tools (2026-08-23)

Both ANTCAP calibration (tools/si4684_antenna_calibration.py) and Si4684 crystal calibration (tools/si4684_xtal_calibration.py, POST /api/tuner/xtal-calibrate) currently exist as host-side Python scripts driving live-but-unpersisted HTTP endpoints — they compute a result but the operator has to hand-edit firmware source (constants in Si4684Driver.cpp / the gSi4684.boot(...) call in hardware_bootstrap.cpp) and reflash to make a result permanent.

Wanted instead: both calibration procedures should be triggerable on-demand from the device itself (an HTTP endpoint is enough — no UI required yet) and, once a result converges, write the result to the 24AA025E48 EEPROM (same chip/pattern already used for ANTCAP persistence, see Eeprom24aa::writeFmAntCap/writeDabAntCap) so it survives a reboot without a firmware reflash. recalibrateXtal() (Si4684Driver.cpp) already does the live re-boot-with-new-params part; what's missing is EEPROM persistence for all three crystal calibration parameters -- ibias, ctun, AND xtalFreqHz (not just XTAL_FREQ; confirmed explicitly 2026-08-24 that all three need to persist, not only the one this session happened to tune) -- plus loading them at boot the same way main.cpp already loads the saved FM/DAB ANTCAP into TunerService before the first tune. ANTCAP already persists this way (2 bytes/band, word addresses 0x00/0x01) — the xtal calibration needs its own new EEPROM word address(es) alongside those (ibias fits in 1 byte, ctun in 1 byte, xtalFreqHz needs 4 bytes -- 6 bytes total, or pack more compactly if EEPROM space is tight). Also still needed: deciding whether the FREQOFF-averaging/damping/ convergence-loop logic (currently in tools/si4684_xtal_calibration.py) moves into firmware, or stays host-side with just an EEPROM-persist step added at the end of the existing HTTP flow.

Not started — explicitly deferred to a future session, noted here only so it isn't lost. See docs/si4684-rf-investigation-report.md's 2026-08-23 entry for full context on why this calibration was needed and how it currently works.

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Quality gates (run from Software/ before merge)

cmake -S components/core/test -B build-host && cmake --build build-host
ctest --test-dir build-host --output-on-failure
doxygen Doxyfile
python3 tools/check-manual-sync.py
python3 tools/check_si4684_blobs.py

After editing the web UI: tools/gzip-www.sh.

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Notes for the agent

• Extend existing patterns (AudioProfile / IAudioProfileStore shape).
• Never invent Si4684 opcodes — cite AN649.
• Never invent BT1035 AT strings — cite Feasycom BT1035 programming guide.
• One logical change per commit; 50/72 messages.
• Update ch-classes.tex / ch-api.tex when public API or HTTP changes.