sx127x-driver v0.0.2
sx127x-driver
Node.js driver for Semtech SX1276/77/78/79 based LoRa radios.
Based on node-sx127x, built on top of @fivdi's onoff and spi-device modules.
Prerequisites
- Linux
- SPI hardware with driver installed and enabled
- for raspberry pi, uncomment
dtparam=spi=on
in/boot/config.txt
- for raspberry pi, uncomment
- Node.js
Hardware Wiring
Semtech SX1276/77/78/79 | Generic Linux | Raspberry Pi |
---|---|---|
VCC | 3.3V | 3.3V |
GND | GND | GND |
SCK | SCK | SCK (pin 11) |
MISO | MISO | MISO (pin 10) |
MOSI | MOSI | MOSI (pin 9) |
NSS | Chip enable/select | CS0 (pin 8) or CS1 (pin 7) |
NRESET | GPIO pin | GPIO pin |
DIO0 | GPIO pin | GPIO pin |
Installation
npm install sx127x-driver
API
Initialize
let SX127x = require('sx127x-driver');
let options = {
// ...
};
let sx127x = new SX127x(options);
Supported options:
Name | Default | Description |
---|---|---|
spiBus | 0 | SPI bus to use |
spiDevice | 0 | SPI chip select/enable to use |
resetPin | 24 | GPIO pin number of reset pin |
dio0Pin | 25 | GPIO pin number of DIO0 pin |
frequency | 915e6 | Frequency of radio in Hz, see setFrequency for supported values (make sure your chip supports the frequency you chose) |
spreadingFactor | 7 | Spreading factor of radio, see setSpreadingFactor for supported values (spreading factors are orthogonal, so make sure they match when trying to communicate from one chip to another) |
signalBandwidth | 125E3 | Signal bandwidth of radio in Hz, see setSignalBandwidth for supported values |
codingRate | 4 / 5 | Coding rate of radio, see setCodingRate for supported values |
preambleLength | 8 | Preamble length of radio, see setPreambleLength for supported values |
syncWord | 0x12 | Sync word of radio, see setSyncWord for supported values |
txPower | 17 | TX power of radio, see setTxPower for supported values |
crc | false | Enable or disable CRC usage |
tempCompensationFactor | false | compensation factor for temperature measurements in degrees celsius (+- some degrees) |
debug | false | enable / disable debug output |
invertIqReg | false | inverts IQ register on call to open() |
Open
Open and configure the device:
try {
await sx127x.open();
} catch(err) {
console.log('Failure to open device: ' + err)
}
Close
Close the device:
try {
await sx127x.close();
} catch (err) {
console.log('Close failure: ' + err);
process.exit();
}
Sending data
try {
await sx127x.write(new Buffer('hello ' + count++));
console.log("successfully sent")
} catch (err) {
console.log('Fail to send: ' + err);
}
Blocking receive
try {
let packetLength = await sx127x.receiveSingle();
if (packetLength > 0) {
let incoming = "";
while (await sx127x.available()) {
incoming += String.fromCharCode(await sx127x.read());
}
}
} catch (err) {
console.log('Fail to receive: ' + err);
}
Interrupt receive
try {
await sx127x.open();
await sx127x.setContinuousReceiveMode();
} catch(err) {
console.log('Fail to put into continuous receive mode: ' + err)
}
sx127x.on('data', function(data, rssi, snr) {
console.log('data: ' + data.toString() + ", rssi: " + rssi);
});
Sleep mode
Put the radio in sleep mode.
try {
await sx127x.sleep();
} catch (err) {
console.log('Fail to put into sleep mode: ' + err);
}
Stand by mode
Put the radio in stand by mode.
try {
await sx127x.standBy();
} catch (err) {
console.log('Fail to put into stand by: ' + err);
}
Radio parameters
TX Power
Change the TX power of the radio.
try {
await sx127x.setTxPower(txPower);
} catch (err) {
console.log(err);
}
txPower
- TX power in dB, defaults to17
Supported values are between
2
and17
.
Frequency
Change the frequency of the radio.
try {
await sx127x.setFrequency(frequency);
} catch (err) {
console.log(err);
}
frequency
- frequency in Hz (433E6
,866E6
,915E6
)
Spreading Factor
Change the spreading factor of the radio.
try {
await sx127x.setSpreadingFactor(spreadingFactor);
} catch (err) {
console.log(err);
}
spreadingFactor
- spreading factor, defaults to7
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.
try {
await sx127x.setSignalBandwidth(signalBandwidth);
} catch (err) {
console.log(err);
}
signalBandwidth
- signal bandwidth in Hz, defaults to125E3
.
Supported values are 7.8E3
, 10.4E3
, 15.6E3
, 20.8E3
, 31.25E3
, 41.7E3
, 62.5E3
, 125E3
, 250E3
and 500E3
.
Coding Rate
Change the coding rate of the radio.
try {
await sx127x.setCodingRate(codingRate);
} catch (err) {
console.log(err);
}
codingRate
- coding rate, defaults to4/5
Supported values are 4/5
, 4/6
, 4/7
and 4/8
.
Preamble Length
Change the preamble length of the radio.
try {
await sx127x.setPreambleLength(preambleLength);
} catch (err) {
console.log(err);
}
preambleLength
- preamble length in symbols, defaults to8
Supported values are between 6
and 65535
.
Sync Word
Change the sync word of the radio.
try {
await sx127x.setSyncWord(syncWord);
} catch (err) {
console.log(err);
}
syncWord
- byte value to use as the sync word, defaults to0x34
CRC
Enable or disable CRC usage, by default a CRC is not used.
try {
await sx127x.setCrc(crc);
} catch (err) {
console.log(err);
}
crc
-true
to enable CRC,false
to disable
Other functions
Random
Generate a random byte, based on the Wideband RSSI measurement.
try {
let random = await sx127x.readRandom(crc);
} catch (err) {
console.log(err);
}
Examples
See examples folder.
License
This library is licensed under the MIT Licence.