Settings NVS

Settings / NVS

All persistent state lives in NVS under namespaces declared in components/mc_domain/settings_nvs.h and components/mc_domain/identity.h (the system namespace is shared with the launcher for owner_name).

Persistent keys

`lora` namespace (`settings_nvs.c`)

Key	Type	Default	Range / values
`freq`	u32	869_618_000 Hz	EU 868 ISM band
`sf`	u8	8	7..12
`bw`	u32	62 (kHz)	7, 10, 15, 20, 31, 41, 62, 125, 250, 500
`cr`	u8	8	5..8 (4/5..4/8)
`pwr`	i8	22 dBm	-9..22 (chip limit)
`sync`	u8	0x2B	0x00..0xFF (0x12 = public LoRa)
`preamble`	u16	16	6..65535
`fldadv_s`	u16	0 (off)	0, else 30s..24h — periodic flood advert
`diradv_s`	u16	0 (off)	0, else 30s..24h — periodic direct advert
`role`	u8	`CHAT_NODE`	`CHAT_NODE` / `REPEATER` / `ROOM_SERVER` / `SENSOR`
`path_h`	u8	1	1..3 (see protocol page)
`country`	str(4)	`"--"`	ISO 3166-1 alpha-2; `"--"` = none (no checks)
`antgain`	i8	0 dBi	-3..15; editable only once `country` ≠ `"--"`
`rxboost`	u8	1 (on)	1 = boosted RX (+3 dB sensitivity), 0 = power-save
`gps.lat`	i32	—	Latitude ×1e6 (advert position + Nodes Dist column)
`gps.lon`	i32	—	Longitude ×1e6

All of the above live in the single system NVS namespace under dotted key names (lora.freq, lora.country, …); the lora. prefix is logical, not a separate namespace.

`system` namespace (shared with launcher)

Key	Type	Purpose
`owner_name`	str (≤32)	Owner display name (shared with launcher)
`last_time_s`	i64	Last good SNTP timestamp; restored on boot without WiFi
`gps_lat_e6`	i32	Saved latitude × 1e6 (MeshCore upstream scale)
`gps_lon_e6`	i32	Saved longitude × 1e6
`gps_valid`	u8	1 if `gps_lat_e6`/`gps_lon_e6` hold a real fix, 0 otherwise
`gps_src`	u8	Source tag: 0=none, 1=manual, 2=PA1010D, 3=USB-CDC, 4=BLE, 5=HTTPS `/ping`
`ble_enabled`	u8	0/1 — NimBLE companion radio on next start
`ble_gps_pref`	u8	iPhone-app mirror of "share my position in adverts"
`adv_loc_pol`	u8	`ADVERT_LOC_NONE` (0) / `ADVERT_LOC_SHARE` (1) — same toggle from the iPhone app, used by the ADVERT serializer
`http_api_key`	str (64)	Shared secret for the HTTPS `/ping` endpoint. Auto-generated 64 hex chars on first boot if missing. Rotated by Settings → Network → Regenerate API key.
`ant_gain`	i8	Antenna gain in dBi; ERP/EIRP power-check input

`http_cert` namespace (per-badge HTTPS cert)

Per-badge ECDSA P-256 self-signed cert generated on first boot and persisted across reflashes. See GPS sources → HTTPS /ping for the iPhone profile install dance.

Key	Type	Purpose
`cert_pem`	str (PEM)	X.509 cert with SAN `DNS:tanmatsu.local`, `DNS:tanmatsu`, 10-year validity
`key_pem`	str (PEM)	ECDSA P-256 private key

Both wiped + regenerated by Settings → Network → Regenerate cert. Triggers a full HTTPS server restart, so the iPhone profile install must be repeated after a regen.

Sound preferences (in `system` namespace)

Key	Type	Default	Purpose
`snd_vol`	u8	50	Master volume 0..100 %
`snd_dm`	u8	1	WAV slot for DM RX (0=off, 1..4 = `/sd/meshcore/sounds/<n>.wav`)
`snd_ch`	u8	2	WAV slot for channel RX
`snd_err`	u8	3	WAV slot for the error event (played on error paths and the Sounds preview)
`snd_boot`	u8	4	WAV slot played at end of `app_main` init

`ui` keys (per-app brightness, in `system` namespace)

Per-app overrides for the three BSP backlight / LED globals. Applied on boot by apply_brightness() and again on every value change in the Brightness settings category, so the launcher's globals stay untouched once MeshCore is running. All three are u8, range 0..100 %, defaults chosen to match the backlog #47 trade-off (battery vs. visibility).

Key	Type	Default	BSP call
`ui.disp_bl`	u8	50	`bsp_display_set_backlight_brightness(pct)`
`ui.kb_bl`	u8	50	`bsp_input_set_backlight_brightness(pct)`
`ui.led_br`	u8	5	`bsp_led_set_brightness(pct)`

Edited via Settings → Brightness; the slider cycles through 5 / 10 / 25 / 50 / 75 / 100 % stops. The launcher's globals are NOT restored on exit — BadgeVMS PIE ELF apps have no clean exit hook, so the MeshCore value persists until the launcher writes its own value next time the launcher's brightness UI runs.

`map` keys (VIEW_MAP state, in `system` namespace)

Dotted map.* keys persisting the map view's centre, zoom, lock toggle and style. Loaded on boot by map_state_init / load_map_profile; centre + zoom are debounce-saved while panning. All in the single system namespace.

Key	Type	Default	Range / values
`map.lat_e6`	i32	Den Haag fallback	Centre latitude × 1e6
`map.lon_e6`	i32	Den Haag fallback	Centre longitude × 1e6
`map.zoom`	u8	8	6..17
`map.lock`	u8	1 (on)	Lock-to-GPS toggle
`map.profile`	u8	`MAP_PROFILE_CARTO`	`map_profile_t`; the loader clamps a stored-but-disabled style to the first entry of `MAP_PROFILES_ENABLED[]` (Carto-only by default — see Maps)

`mc` namespace (MeshCore-specific identity)

Key	Type	Purpose
`adv_name`	str (≤32)	Overrides `owner_name` in adverts when non-empty
`region`	str (≤8)	Region scope tag (NL, DE, …)
`node_pub`	blob 32	Ed25519 public key
`node_prv`	blob 32	Ed25519 private key

`contacts` namespace (`contacts.c`)

Key	Type	Purpose
`count`	u8	Number of saved contacts
`c<n>`	blob	Contact n: pub key + alias + role

MAX_CONTACTS = 16; pubkey-prefix collisions are accepted but rare in practice.

C6 sync flow

The C6 also holds its own copy of LoRa config. On boot:

load_lora_from_nvs reads the P4 copy into lora_cfg.
lora_get_config(&c6_cfg) reads the C6 copy.
If c6_cfg.frequency != 0, the C6 wins → lora_cfg = c6_cfg and we persist back to NVS.
If c6_cfg.frequency == 0 (blank — typical after a fresh radio flash), we push lora_cfg to the C6 with lora_set_config(&lora_cfg).

Edits in the Settings tab call save_lora_to_nvs and lora_set_config immediately on save, so the two copies stay in sync.

LoRa presets

settings_nvs.c carries a LORA_PRESETS[] table. Selecting a preset in the Settings tab overwrites SF, BW, CR (and sync word for the MeshCore preset). Frequency, TX power, preamble and role are not touched by presets.

Default presets shipped:

Name	SF	BW	CR	Notes
MeshCore	8	62	4/6	Matches stock MeshCore default net
LongFast	11	250	4/5	Meshtastic-style fast & long-range
LongSlow	12	125	4/8	Maximum range, very slow
ShortFast	7	500	4/5	Local, high throughput

When a custom combination is active the Settings row shows (custom).

Regulatory compliance

components/mc_proto/region_limits.{h,c} carries a per-country table of the licence-exempt ISM-band rules. Picking a Country in the Settings tab drives three things: off-band / over-power warnings, the antenna-gain → ERP/EIRP calculation, and a hard duty-cycle budget enforced in radio.c.

Enforcement model

Limit	Mode	Where
Frequency outside any sub-band	soft — Country/Frequency rows turn red, footer hint	`render.c`
Effective power > sub-band max	soft — TX power row turns red	`render.c` (`region_effective_power_dbm`)
Duty cycle (rolling 1 h airtime)	hard — TX blocked when budget spent	`radio.c` (Semtech time-on-air)

The split is deliberate: a wrong frequency or a few dB over is the operator's call to make (they may have a licence, or a directional antenna), but airtime hogging actively degrades the shared mesh, so the duty-cycle cap is enforced.

The data table is a guidance helper, not legal advice. It is also an interim app-side implementation — radio-side enforcement may move into the C6 firmware once upstream tanmatsu-radio grows a compliance layer.

Data schema

typedef struct {
    float    freq_min_mhz, freq_max_mhz;
    int8_t   max_power_dbm;        // unit per containing country (ERP or EIRP)
    uint16_t duty_cycle_permille;  // 1000 = none, 100 = 10%, 10 = 1%, 1 = 0.1%
    bool     lbt_alternative;      // LBT may replace duty cycle (informational)
    uint16_t max_dwell_time_ms;    // 0 = none (FCC FHSS = 400)
    const char *label;             // e.g. "g3"
} regulatory_subband_t;

typedef struct {
    const char *country_code;      // ISO 3166-1 alpha-2
    const char *display_name;
    power_unit_t power_unit;       // POWER_UNIT_ERP | POWER_UNIT_EIRP
    const regulatory_subband_t *subbands;
    uint8_t n_subbands;
} regulatory_country_t;

ERP vs EIRP

The EU regulates in ERP (dipole reference); the US/JP/AU/NZ/etc in EIRP (isotropic). The app converts your conducted TX power to the country's unit before comparing against the limit:

ERP  = conducted_dBm + antenna_gain_dBi − 2.15
EIRP = conducted_dBm + antenna_gain_dBi

So at the SX1262's 22 dBm conducted ceiling with a 0 dBi antenna you radiate ~19.85 dBm ERP — comfortably under the EU g3 limit of 27 dBm ERP.

EU 863–870 MHz sub-bands (ERP) — `EU868_SUBBANDS`

Band	Range (MHz)	Max power	Duty cycle
g	863.0–865.0	14 dBm	0.1%
g1	865.0–868.0	14 dBm	1%
g1'	868.0–868.6	14 dBm	1%
g2	868.7–869.2	14 dBm	0.1%
g3	869.4–869.65	27 dBm	10%
g4	869.7–870.0	14 dBm	1%

Used by: NL, BE, DE, AT, FR, CH, UK, IT, ES, PT, SE, NO, DK, FI, PL, CZ, IE, UA, ZA (19 countries). Default 869.618 MHz → g3.

Other regions

Constant	Countries	Range (MHz)	Max power	Duty / dwell
`EU433_SUBBANDS`	433 SRD	433.05–434.79	10 dBm ERP	10%
`US915_SUBBANDS`	US, CA, MX	902–928	30 dBm EIRP	none (FHSS dwell 400 ms info)
`ANZ915_SUBBANDS`	AU, NZ	915–928	30 dBm EIRP	none
`JP920_SUBBANDS`	JP	920.5–923.5	13 dBm EIRP	10% + LBT required
`KR920_SUBBANDS`	KR	920.0–923.0	14 dBm EIRP	10%
`IN865_SUBBANDS`	IN	865.0–867.0	30 dBm EIRP	none
`RU864_SUBBANDS`	RU	864–865 / 868.7–869.2	14 dBm ERP	0.1%

Duty-cycle accounting

radio.c keeps 60 one-minute airtime buckets (rolling hour). Every TX path estimates on-air time with the Semtech LoRa time-on-air formula (AN1200.13) and checks dc_budget_available() before sending; region_dc_budget_ms_per_hour turns the sub-band's permille into the ms/hour budget (10% → 360 000 ms). The Settings Duty cycle (1h) row surfaces used.x% (used s / budget s) and appends BLOCKED when a send was just refused.

Sources

EU 863–870: ETSI EN 300 220 V3.2.1 + ERC-REC-70-03
US 902–928: FCC Part 15.247 / 15.249
Country→band mapping: Lansitec LoRaWAN frequency-plan reference
Cross-check only: Meshtastic src/mesh/RadioInterface.cpp (it collapses each region to a single sub-band; we keep full EU sub-band granularity)

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Settings NVS

Settings / NVS

Persistent keys

`lora` namespace (`settings_nvs.c`)

`system` namespace (shared with launcher)

`http_cert` namespace (per-badge HTTPS cert)

Sound preferences (in `system` namespace)

`ui` keys (per-app brightness, in `system` namespace)

`map` keys (VIEW_MAP state, in `system` namespace)

`mc` namespace (MeshCore-specific identity)

`contacts` namespace (`contacts.c`)

C6 sync flow

LoRa presets

Regulatory compliance

Enforcement model

Data schema

ERP vs EIRP

EU 863–870 MHz sub-bands (ERP) — `EU868_SUBBANDS`

Other regions

Duty-cycle accounting

Sources

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Settings NVS

Settings / NVS

Persistent keys

lora namespace (settings_nvs.c)

system namespace (shared with launcher)

http_cert namespace (per-badge HTTPS cert)

Sound preferences (in system namespace)

ui keys (per-app brightness, in system namespace)

map keys (VIEW_MAP state, in system namespace)

mc namespace (MeshCore-specific identity)

contacts namespace (contacts.c)

C6 sync flow

LoRa presets

Regulatory compliance

Enforcement model

Data schema

ERP vs EIRP

EU 863–870 MHz sub-bands (ERP) — EU868_SUBBANDS

Other regions

Duty-cycle accounting

Sources

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Clone this wiki locally

`lora` namespace (`settings_nvs.c`)

`system` namespace (shared with launcher)

`http_cert` namespace (per-badge HTTPS cert)

Sound preferences (in `system` namespace)

`ui` keys (per-app brightness, in `system` namespace)

`map` keys (VIEW_MAP state, in `system` namespace)

`mc` namespace (MeshCore-specific identity)

`contacts` namespace (`contacts.c`)

EU 863–870 MHz sub-bands (ERP) — `EU868_SUBBANDS`