C3MA/DD3-LoRa-Bridge-MultiSender
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Validate RTC epoch before setting time

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- Reject out-of-range DS3231 epochs and log accept/reject under SERIAL_DEBUG_MODE
- Document RTC validation so LoRa TimeSync can recover
This commit is contained in:
acidburns
2026-02-04 00:31:10 +01:00
parent e8fb8680cb
commit e0d35d49bc
2 changed files with 13 additions and 0 deletions
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1
README.md
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@@ -306,6 +306,7 @@ inline constexpr uint16_t EXPECTED_SENDER_IDS[NUM_SENDERS] = { 0xF19C };
- Receiver keeps sending time sync every 60 seconds. - Receiver keeps sending time sync every 60 seconds.
- If a sender’s timestamps drift from receiver time by more than `TIME_SYNC_DRIFT_THRESHOLD_SEC`, the receiver enters a burst mode (every `TIME_SYNC_BURST_INTERVAL_MS` for `TIME_SYNC_BURST_DURATION_MS`). - If a sender’s timestamps drift from receiver time by more than `TIME_SYNC_DRIFT_THRESHOLD_SEC`, the receiver enters a burst mode (every `TIME_SYNC_BURST_INTERVAL_MS` for `TIME_SYNC_BURST_DURATION_MS`).
- Sender raises a local `TimeSync` error if it has not received a time beacon for `TIME_SYNC_ERROR_TIMEOUT_MS` (default 2 days). This is shown on the sender OLED only and is not sent over LoRa. - Sender raises a local `TimeSync` error if it has not received a time beacon for `TIME_SYNC_ERROR_TIMEOUT_MS` (default 2 days). This is shown on the sender OLED only and is not sent over LoRa.
- RTC loads are validated (reject out-of-range epochs) so LoRa TimeSync can recover if the RTC is wrong.
## Build Environments ## Build Environments
- `lilygo-t3-v1-6-1`: production build (debug on) - `lilygo-t3-v1-6-1`: production build (debug on)

12
src/time_manager.cpp
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@@ -8,6 +8,8 @@ static bool g_time_synced = false;
static bool g_tz_set = false; static bool g_tz_set = false;
static bool g_rtc_present = false; static bool g_rtc_present = false;
static uint32_t g_last_sync_utc = 0; static uint32_t g_last_sync_utc = 0;
static constexpr uint32_t kMinValidEpoch = 1672531200UL; // 2023-01-01
static constexpr uint32_t kMaxValidEpoch = 4102444800UL; // 2100-01-01
static void note_last_sync(uint32_t epoch) { static void note_last_sync(uint32_t epoch) {
if (epoch == 0) { if (epoch == 0) {
@@ -142,6 +144,16 @@ bool time_try_load_from_rtc() {
} }
uint32_t epoch = 0; uint32_t epoch = 0;
if (!rtc_ds3231_read_epoch(epoch) || epoch == 0) { if (!rtc_ds3231_read_epoch(epoch) || epoch == 0) {
if (SERIAL_DEBUG_MODE) {
Serial.println("rtc: read failed");
}
return false;
}
bool valid = epoch >= kMinValidEpoch && epoch <= kMaxValidEpoch;
if (SERIAL_DEBUG_MODE) {
Serial.printf("rtc: epoch=%lu %s\n", static_cast<unsigned long>(epoch), valid ? "accepted" : "rejected");
}
if (!valid) {
return false; return false;
} }
time_set_utc(epoch); time_set_utc(epoch);