In the release build of the Oyster LoRaWAN, the LED is operational from reset until the first sleep. Thereafter, it is disabled for power saving reasons.
After reset the following will be observed:
- A single 1 second flash on reset.
- An additional 10 seconds of the LED on if a brownout is detected. After which the device will sleep for 3 hours before attempting further transmissions. The reason for this cautious approach to startup on low batteries is respect for the duty cycle restrictions - repeated resets could lead to repeated transmissions, and breaking of the duty cycle laws. Repeated requests can also use up the limited number of Join Requests that a LoRaWAN 1.1 device may send before being re-provisioned (65 thousand).
- The device will attempt to join the network. The LED will flash at 2Hz during this period (250ms on, 250ms off). The device may fail, and back off until the duty cycle restrictions allows it to retry (30-120 seconds, 3 tries). The LED will be off during the back-off time. In firmware versions >= 1.8, it will flash again during the retry. In versions < 1.8, it will be off after any join failure.
- The device will then turn on the GPS. While attempting to get a fix, the GPS will flash at 1Hz (500ms on, 500ms off). The LED may not show this if it had to retry the join in step 3 (firmware < 1.8).
- The device will then transmit the GPS fix. This will be another 2Hz flash for the duration of the transmission - which is effectively 2 short flashes.
If the config cable is plugged in, the LED will be on constantly. Once removed, if the settings have changed, the device will reset, and start the behavior described above.
If a firmware update is incomplete, the LED will go on permanently. To complete the update, plug the cable in again and run the config app.