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