# LoRa API ## Include Library ```arduino #include ``` ## Setup ### Begin Initialize the library with the specified frequency. ```arduino LoRa.begin(frequency); ``` * `frequency` - frequency in Hz (`433E6`, `866E6`, `915E6`) Returns `1` on success, `0` on failure. ### Set pins Override the default `NSS`, `NRESET`, and `DIO0` pins used by the library. **Must** be called before `LoRa.begin()`. ```arduino LoRa.setPins(ss, reset, dio0); ``` * `ss` - new slave select pin to use, defaults to `10` * `reset` - new reset pin to use, defaults to `9` * `dio0` - new DIO0 pin to use, defaults to `2`. **Must** be interrupt capable via [attachInterrupt(...)](https://www.arduino.cc/en/Reference/AttachInterrupt). This call is optional and only needs to be used if you need to change the default pins used. #### No MCU controlled reset pin To save further pins one could connect the reset pin of the MCU with reset pin of the radio thus resetting only during startup. * `reset` - set to `-1` to omit this pin ### Set SPI interface Override the default SPI interface used by the library. **Must** be called before `LoRa.begin()`. ```arduino LoRa.setSPI(spi); ``` * `spi` - new SPI interface to use, defaults to `SPI` This call is optional and only needs to be used if you need to change the default SPI interface used, in the case your Arduino (or compatible) board has more than one SPI interface present. ### Set SPI Frequency Override the default SPI frequency of 10 MHz used by the library. **Must** be called before `LoRa.begin()`. ```arduino LoRa.setSPIFrequency(frequency); ``` * `frequency` - new SPI frequency to use, defaults to `8E6` This call is optional and only needs to be used if you need to change the default SPI frequency used. Some logic level converters cannot support high speeds such as 8 MHz, so a lower SPI frequency can be selected with `LoRa.setSPIFrequency(frequency)`. ### End Stop the library ```arduino LoRa.end() ``` ## Sending data ### Begin packet Start the sequence of sending a packet. ```arduino LoRa.beginPacket(); LoRa.beginPacket(implicitHeader); ``` * `implicitHeader` - (optional) `true` enables implicit header mode, `false` enables explicit header mode (default) Returns `1` if radio is ready to transmit, `0` if busy or on failure. ### Writing Write data to the packet. Each packet can contain up to 255 bytes. ```arduino LoRa.write(byte); LoRa.write(buffer, length); ``` * `byte` - single byte to write to packet or * `buffer` - data to write to packet * `length` - size of data to write Returns the number of bytes written. **Note:** Other Arduino `Print` API's can also be used to write data into the packet ### End packet End the sequence of sending a packet. ```arduino LoRa.endPacket(); LoRa.endPacket(async); ``` * `async` - (optional) `true` enables non-blocking mode, `false` waits for transmission to be completed (default) Returns `1` on success, `0` on failure. ## Receiving data ### Parsing packet Check if a packet has been received. ```arduino int packetSize = LoRa.parsePacket(); int packetSize = LoRa.parsePacket(size); ``` * `size` - (optional) if `> 0` implicit header mode is enabled with the expected a packet of `size` bytes, default mode is explicit header mode Returns the packet size in bytes or `0` if no packet was received. ### Continuous receive mode **WARNING**: Not supported on the Arduino MKR WAN 1300 board! #### Register callback Register a callback function for when a packet is received. ```arduino LoRa.onReceive(onReceive); void onReceive(int packetSize) { // ... } ``` * `onReceive` - function to call when a packet is received. #### Receive mode Puts the radio in continuous receive mode. ```arduino LoRa.receive(); LoRa.receive(int size); ``` * `size` - (optional) if `> 0` implicit header mode is enabled with the expected a packet of `size` bytes, default mode is explicit header mode The `onReceive` callback will be called when a packet is received. ### Packet RSSI ```arduino int rssi = LoRa.packetRssi(); ``` Returns the RSSI of the received packet. ### Packet SNR ```arduino float snr = LoRa.packetSnr(); ``` Returns the estimated SNR of the received packet in dB. ### Packet Frequency Error ```arduino long freqErr = LoRa.packetFrequencyError(); ``` Returns the frequency error of the received packet in Hz. The frequency error is the frequency offset between the receiver centre frequency and that of an incoming LoRa signal. ### Available ```arduino int availableBytes = LoRa.available() ``` Returns number of bytes available for reading. ### Peeking Peek at the next byte in the packet. ```arduino byte b = LoRa.peek(); ``` Returns the next byte in the packet or `-1` if no bytes are available. ### Reading Read the next byte from the packet. ```arduino byte b = LoRa.read(); ``` Returns the next byte in the packet or `-1` if no bytes are available. **Note:** Other Arduino [`Stream` API's](https://www.arduino.cc/en/Reference/Stream) can also be used to read data from the packet ## Other radio modes ### Idle mode Put the radio in idle (standby) mode. ```arduino LoRa.idle(); ``` ### Sleep mode Put the radio in sleep mode. ```arduino LoRa.sleep(); ``` ## Radio parameters ### TX Power Change the TX power of the radio. ```arduino LoRa.setTxPower(txPower); LoRa.setTxPower(txPower, outputPin); ``` * `txPower` - TX power in dB, defaults to `17` * `outputPin` - (optional) PA output pin, supported values are `PA_OUTPUT_RFO_PIN` and `PA_OUTPUT_PA_BOOST_PIN`, defaults to `PA_OUTPUT_PA_BOOST_PIN`. Supported values are `2` to `20` for `PA_OUTPUT_PA_BOOST_PIN`, and `0` to `14` for `PA_OUTPUT_RFO_PIN`. Most modules have the PA output pin connected to PA BOOST, ### Frequency Change the frequency of the radio. ```arduino LoRa.setFrequency(frequency); ``` * `frequency` - frequency in Hz (`433E6`, `866E6`, `915E6`) ### Spreading Factor Change the spreading factor of the radio. ```arduino LoRa.setSpreadingFactor(spreadingFactor); ``` * `spreadingFactor` - spreading factor, defaults to `7` Supported values are between `6` and `12`. If a spreading factor of `6` is set, implicit header mode must be used to transmit and receive packets. ### Signal Bandwidth Change the signal bandwidth of the radio. ```arduino LoRa.setSignalBandwidth(signalBandwidth); ``` * `signalBandwidth` - signal bandwidth in Hz, defaults to `125E3`. Supported values are `7.8E3`, `10.4E3`, `15.6E3`, `20.8E3`, `31.25E3`, `41.7E3`, `62.5E3`, `125E3`, and `250E3`. ### Coding Rate Change the coding rate of the radio. ```arduino LoRa.setCodingRate4(codingRateDenominator); ``` * `codingRateDenominator` - denominator of the coding rate, defaults to `5` Supported values are between `5` and `8`, these correspond to coding rates of `4/5` and `4/8`. The coding rate numerator is fixed at `4`. ### Preamble Length Change the preamble length of the radio. ```arduino LoRa.setPreambleLength(preambleLength); ``` * `preambleLength` - preamble length in symbols, defaults to `8` Supported values are between `6` and `65535`. ### Sync Word Change the sync word of the radio. ```arduino LoRa.setSyncWord(syncWord); ``` * `syncWord` - byte value to use as the sync word, defaults to `0x12` ### CRC Enable or disable CRC usage, by default a CRC is not used. ```arduino LoRa.enableCrc(); LoRa.disableCrc(); ``` ### Invert IQ Signals Enable or disable Invert the LoRa I and Q signals, by default a invertIQ is not used. ```arduino LoRa.enableInvertIQ(); LoRa.disableInvertIQ(); ``` ## Other functions ### Random Generate a random byte, based on the Wideband RSSI measurement. ``` byte b = LoRa.random(); ``` Returns random byte.