Add function to invert IQ signal register.

[ricaun]

InvertIQ allows differentiating sender and receiver message.

Usually, Gateways read messages with InvertIQ off and send messages with InvertIQ on, Nodes read messages with InvertIQ on and send messages with InvertIQ off.

This way a Gateway only reads messages from Nodes and never reads messages from other Gateway, and Node never reads messages from other Node.

I already test in my fork. Only need to add this code.

#define REG_INVERTIQ             0x33

void LoRaClass::invertIQ(boolean invert)
{
  writeRegister(REG_INVERTIQ , invert == false ? 0x27 : 0x66);
}

Thanks

[morganrallen]

It would be great to see this as a full PR. Should be able to just add it to LoRa.h and API.md

[halukmy]

@morganrallen did he added?

[halukmy]

@ricaun hey Luiz, how nodes understand other one is not node? or gateway?

for example , i am using this lib as gateway too,

is 0x27 gateway or 0x66 node?

[ricaun]

@halukmy I create two examples, https://github.com/ricaun/arduino-LoRa/tree/master/examples

Basically Gateway send message with invertIQ enable and receive with invertIQ disabled. Nodes sends message with invertIQ disabled and receive message with invertIQ enable.

LoRaWan use this arrangement, with invertIQ enable is possible to sniff downlink packages.

[sandeepmistry]

Closed via https://github.com/sandeepmistry/arduino-LoRa/pull/179.