Flashing the Firmware

Flashing the Firmware

NaviCore targets the WCB v3.2 board (ESP32‑S3). There are several ways to get firmware onto a board: the in‑browser flasher (easiest), the ESP Flasher Companion desktop app, the Arduino IDE, or the build scripts / CI.

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Option 1 — In‑browser flasher (recommended)

The config tool can flash a connected board directly over USB, pulling the latest compiled binaries from the repo's firmware/ folder.

1. Open config_tool/index.html in Chrome or Edge (Web Serial is required — Firefox/Safari won't work).
2. Plug the board in over USB.
3. Go to Config → Firmware.
4. Choose one of:
   • ⬆ Update Firmware — routine update. Writes the bootloader, partition table, and app, but never touches the data partitions (the LittleFS /config.json store or NVS), so your saved configuration is preserved.
   • ⚠ Full Wipe & Flash — initial programming or recovery. Writes the same image and erases NVS (legacy/migration store) plus OTA data. Note: it does not erase the LittleFS partition, so the current /config.json survives — to clear a bad config use Restore Defaults (RESET_DEFAULTS) instead. Use Full Wipe the first time you program a new board, or to clear stale OTA/NVS state.

Both modes write the same three regions (bootloader + partition table + app); the only difference is whether NVS + OTA data is also erased (neither mode touches the LittleFS config partition). The flasher reuses the port you're already connected on (no second port picker) and reconnects to the board automatically once it reboots — no need to re‑select the port afterward.

The page fetches binaries from main by default. (Developers can target another branch by setting localStorage.rc_fw_branch = '<branch>' in DevTools.)

The flasher uses esptool over Web Serial and needs a direct USB connection — you cannot flash through a "Via WCB" bridge. (The flash buttons are disabled while Via WCB is active.)

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Option 2 — ESP Flasher Companion (desktop)

A small desktop app (greghulette/ESP-Flasher-Companion) that flashes the WCB‑family boards — WCB, NaviCore, and the SBUS Controller — over USB from a single window. Each board row has its own port, a Build + Flash, a Restore Bootloader, and an Identify button, with a shared flash log.

Why it matters for NaviCore: Build + Flash writes the custom short‑WDT bootloader and the partition table (plus OTA data and the app) — not just the app — the same bootloader/partition pairing the WCB hardware needs. Restore Bootloader re‑installs just that bootloader if a stock one ever overwrites it. It flashes with --after watchdog-reset so the ESP32‑S3 doesn't bounce straight back into download mode after writing.

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Option 3 — Arduino IDE

1. Open NaviCore.ino in the Arduino IDE.
2. Tools → Board → ESP32S3 Dev Module (or your usual WCB v3.2 board definition).
3. Tools → Partition Scheme → Minimal SPIFFS (1.9 MB APP with OTA / 190 KB SPIFFS).
4. Tools → USB CDC On Boot → Enabled (so Serial is native USB‑CDC; the firmware relies on this for the SBUS‑out UART allocation).
5. Tools → PSRAM → OPI PSRAM — required. The firmware allocates its ~210 KB runtime configuration in external PSRAM at boot; if PSRAM is disabled (or set to QSPI) the allocation fails and the board halts with a solid red status LED. The WCB v3.2's ESP32‑S3‑WROOM‑1 N16R8 module has 8 MB of octal PSRAM, hence "OPI".
6. Sketch → Upload, or Export Compiled Binary to produce the three .bin files.

Required libraries

Install via Library Manager (versions pinned to match CI — ArduinoJson must be v7; v6's DynamicJsonDocument allocation behavior breaks SET_CONFIG parsing):

• ArduinoJson (Benoit Blanchon) — 7.4.3
• EspSoftwareSerial — 8.1.0 (for S3/S4)
• Adafruit NeoPixel — 1.15.4
• PololuMaestro

Local library (drop into your sketchbook libraries/ folder):

• WCB_Client + WCBStream (from the greghulette/WCBClient repo)

The exact library set + versions live in .github/workflows/build-firmware.yml — that workflow is the source of truth, so check there if a build ever disagrees with this list.

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Option 4 — Build scripts & CI

• CI (default): every push triggers .github/workflows/build-firmware.yml, which compiles NaviCore.ino for ESP32‑S3, reads the version from fw_version.h, and commits the three .bin files back into firmware/ (tagged [skip ci]). Once that lands on main, the in‑browser flasher can use it.
• Local: run tools/build-firmware.ps1 (Windows) or tools/build-firmware.sh (Linux/macOS/WSL). Both wrap arduino-cli with the correct FQBN + partition scheme and drop versioned bins into firmware/. Prereqs: arduino-cli, the esp32 core, and the library set from the CI workflow.

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Firmware files & flash addresses

Three files per release, matched by suffix (the version prefix can change every build):

File suffix	Flash address	Purpose
_ESP32S3.bin	0x10000	Application image (ota_0)
_ESP32S3_boot.bin	0x0	Second‑stage bootloader
_ESP32S3_part.bin	0x8000	Partition table

NVS lives at 0x9000; OTA data at 0xE000; the saved config now lives in the LittleFS data (spiffs) partition. Update Firmware leaves all of them alone; Full Wipe & Flash erases NVS and OTA data only — the LittleFS config partition is untouched by either mode.

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Versioning

The version lives in fw_version.h at the repo root:

#define FW_VERSION_BASE  "v0.2.0"         // bump by hand for releases
#define FW_VERSION_DTG   "011009QJUN26"   // auto-stamped by the pre-commit hook
#define FW_VERSION       FW_VERSION_BASE "_" FW_VERSION_DTG

• FW_VERSION_BASE — semver; edit by hand when cutting a release (v0.2.0 → v0.2.1 → v0.3.0 → v1.0.0).
• FW_VERSION_DTG — a Date‑Time‑Group stamped automatically by tools/git-hooks/pre-commit on every commit. Don't edit by hand.

The build embeds both into the .bin filename, and the firmware reports FW_VERSION in its boot banner and in the PONG reply — so the file on disk, the running version, and the source header always match. The config tool shows the connected board's version in its footer and on the Firmware tab.

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