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SX1278 API

Include Library

#include "SX1278.h"

Setup

Begin

Initialize the library with the specified frequency.

loRa.begin(433775000);
  • frequency - frequency in Hz (433E6, 868E6, 915E6)

Set pins

Override the default NSS, NRESET, and DIO0 pins used by the library. Must be called before LoRa.begin().

loRa.setPins(channel, reset, DIO_0);
  • channel - new slave channel pin to use, defaults CE0 to 0
  • reset - new reset pin to use, defaults to 0
  • dio0 - new DIO0 pin to use, defaults to 22. Must be interrupt capable via wiringPiISR.

This call is optional and only needs to be used if you need to change the default pins used.

Pin dio0 interrupt callbacks

The dio0 pin can be used for channel activity detection callback, transmission finish callback and/or receiving callback, check onTxDone, and onRxDone.

Sending data

Begin packet

Start the sequence of sending a packet.

loRa << beginPacket;

Writing

Write data to the packet. Each packet can contain up to 255 bytes.

loRa << "Welcome LoRa";

or

 send(buffer, length)
  • buffer - char* data to write to packet
  • length - int size of data to write
char buffer[] = "message";
loRa.send(buffer, sizeof(buffer));

End packet

End the sequence of sending a packet.

loRa << beginPacket << "welcom LoRa" << endPacket;

Tx Done

WARNING: TxDone callback uses the interrupt pin on the dio0 check setPins function!

Register callback

Register a callback function for when a packet transmission finish.

loRa.onRxDone(callback_Tx);

void callback_Tx() {
 // ...
}
  • callback_Tx - function to call when a packet transmission finish.

Receiving data Rx Done

Continuous receive mode

WARNING: Receive callback uses the interrupt pin on the dio0, check setPins function!

Register callback

Register a callback function for when a packet is received.

loRa.onTxDone(callback_Rx);

void callback_Rx(char* payload, int rssi, float snr) { 
 // ...
}
  • callback_Rx - function to call when a packet is received.
  • payload the char*
  • rssi the averaged RSSI of the last received packet (dBm).
  • snr the estimated SNR of the received packet in dB.

Receive mode

Puts the radio in continuous receive mode.

loRa.continuous_receive();

Radio parameters

Spreading Factor

Change the spreading factor of the radio.

loRa.set_sf(sf);
  • sf - spreading factor, defaults to SF12

Supported values are between SF7 and SF12.

Signal Bandwidth

Change the signal bandwidth of the radio.

loRa.set_bandwidth(bw);
  • bw - signal bandwidth in Hz, defaults to BW125.

Supported values are BW7_8, BW10_4, BW15_6, BW20_8, BW31_25, BW41_7, BW62_5, BW125, BW250, and BW500.

Coding Rate

Change the coding rate of the radio.

loRa.set_errorcrc(cr);;
  • cr - denominator of the coding rate, defaults to CR5

Supported values are between CR5,CR6, CR7 and CR8, these correspond to coding rates of 4/5 4/6 4/7 and 4/8. The coding rate numerator is fixed at 4.

Preamble Length

Change the preamble length of the radio.

loRa.set_preamble(int preambleLen);;
  • preambleLen - preamble length in symbols, defaults to 6

Supported values are between 6 and 65535.

Sync Word

Change the sync word of the radio.

loRa.set_syncw(word);
  • word - byte value to use as the sync word, defaults to 0x12