Hi,
We have a use case where the xDot is operating in AT Command mode with an external MCU issuing the join/send/etc commands. The xDot is powered off completely, and power is reapplied when there is a sensor event and there is data to send to the Conduit. Even when the join mode is set to AUTO_OTA, join sessions are not preserved across power down states (only across sleep). This is a battery consumption issue because it forces us to join on every power-up/sensor event.
I understand this would be easier if we can sleep/wake the xDot rather than having to power it off completely, as the Auto_OTA will save the session credentials in battery-backed registers and can be restored on wake. But if that’s not possible, what options are there to avoid having to re-join every single time but still use OTA / Auto_OTA on the initial join? I don’t see an AT command to write the session keys to flash and have it automatically read session keys from flash on power up. That would be a nice feature, as it gives the user complete control over re-join scheme.
When join mode is set to Auto_OTA, can we still use AT+NA, AT+NSK, and AT+DSK to basically set the credentials on the xDot on a power up? So, a possible scheme might be to AT&V, parse the output for the Network Address, NSK, and DSK, and save it off on external flash on the PIC. Then on power up, AT+NA, AT+NSK, and AT+DSK with the saved credentials? The external MCU can still issue join commands if needed to get valid keys. This seems like a very backwards way of doing it though.
Are there other options?
I wish Auto_OTA saved credentials to flash.