Most LoRa modules work with an operating voltage between 2.1V and 3.6V. Are there any components used in the RAK811 (like the TCXO) which have a limited operational voltage?
A lot of LoRa applications are battery powered and using primary lithium of 3.6V. The power circuit can be kept simpler (saves costs) when the operational voltage of the LoRa module has a wider spec!
@junhua Hi, I also checked this firmware. However, when I send at+sleep the chip responds OK, and when I send again any character to wake up, the radio responses me ERROR, instead of at+recv=8,0,0. Besides, when I put it on sleep mode, I don't need to wake up the module to send a new package. Could you help me with that?