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Persist Si4684 crystal calibration (ibias/ctun/xtalFreqHz) to EEPROM

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Extends the existing FM/DAB ANTCAP EEPROM persistence pattern
(Eeprom24aa::writeFmAntCap/writeDabAntCap) to the crystal trim found by
POST /api/tuner/xtal-calibrate, which previously only applied live and
was lost on every reboot.

- Eeprom24aa gains readXtalCalibration()/writeXtalCalibration() at word
  addresses 0x02 (ibias), 0x03 (ctun), 0x04-0x07 (xtalFreqHz,
  big-endian), right after the existing FM/DAB ANTCAP bytes.
- HardwareBootstrap::boot() now boots ADAU1701 before Si4684 (needed so
  the EEPROM read, which borrows ADAU1701's I2C bus, can happen before
  Si4684's boot() call, which takes the crystal trim as an argument),
  loads the saved trim if present, and falls back to the compiled-in
  defaults (ibias=72, ctun=0, xtalFreqHz=19199750) otherwise.
- POST /api/tuner/xtal-calibrate now persists every successful live
  recalibration automatically ("persisted":true/false in the response)
  via a new saveXtalCalibration()/net::AntennaCalibration::saveXtal
  bridge, mirroring the ANTCAP save pattern.

Verified live: boot log confirms "Xtal not calibrated" before the first
save, "Xtal calibration loaded: ibias=72 ctun=0 xtal_freq_hz=19199750"
after, surviving a reboot; DAB/FM tuning unaffected (DAB CNR 17-19dB,
locked).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
michele
2026-08-25 15:22:03 +02:00
co-authored by Claude Sonnet 5
parent d17902f19c
commit a7a5311c2c
9 changed files with 351 additions and 25 deletions
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Software/docs/TODO.md
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@@ -204,7 +204,7 @@ Done in fw 0.8.5 unless noted:
---
## TODO — calibration functions need to become permanent, in-firmware, on-demand tools (2026-08-23)
## DONE (2026-08-24) — calibration functions are now permanent, in-firmware, on-demand tools
Both ANTCAP calibration (`tools/si4684_antenna_calibration.py`) and Si4684
crystal calibration (`tools/si4684_xtal_calibration.py`,
@@ -236,10 +236,24 @@ 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.
**Resolved 2026-08-24.** `Eeprom24aa` gained `readXtalCalibration()` /
`writeXtalCalibration()` (word addresses 0x02 ibias, 0x03 ctun, 0x04-0x07
xtalFreqHz big-endian, right after the existing FM/DAB ANTCAP bytes at
0x00/0x01). `HardwareBootstrap::boot()` now reads the ADAU1701 boot
earlier (moved before Si4684's, since the EEPROM read needs ADAU1701's
I2C bus) and loads the saved crystal trim before calling
`gSi4684.boot(...)`, falling back to the compiled-in defaults
(ibias=72, ctun=0, xtalFreqHz=19199750) when the EEPROM has never been
calibrated. `POST /api/tuner/xtal-calibrate` now persists every
successful live recalibration automatically (`"persisted":true/false` in
the response) via a new `saveXtalCalibration()` /
`net::AntennaCalibration::saveXtal` bridge, mirroring the existing
ANTCAP save pattern. The convergence-loop logic
(`tools/si4684_xtal_calibration.py`) stays host-side, unchanged — only
the persistence gap was closed.
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.
---