Settings NVS

Settings / NVS

All persistent state lives in NVS under namespaces declared in main/settings_nvs.h and main/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	6	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
adv_int	u32	1800 s	30s..24h
role	u8	CHAT_NODE	CHAT_NODE / REPEATER / ROOM_SERVER / SENSOR
path_h	u8	1	1..3 (see protocol page)

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

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:

1. load_lora_from_nvs reads the P4 copy into lora_cfg.
2. lora_get_config(&c6_cfg) reads the C6 copy.
3. If c6_cfg.frequency != 0, the C6 wins → lora_cfg = c6_cfg and we persist back to NVS.
4. 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).