122 lines
3.5 KiB
C++
122 lines
3.5 KiB
C++
/*
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RadioLib SX127x Transmit with Frequency Hopping Example
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This example transmits packets using SX1278 LoRa radio module.
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Each packet contains up to 256 bytes of data, in the form of:
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- Arduino String
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- null-terminated char array (C-string)
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- arbitrary binary data (byte array)
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Other modules from SX127x/RFM9x family can also be used.
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For default module settings, see the wiki page
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https://github.com/jgromes/RadioLib/wiki/Default-configuration#sx127xrfm9x---lora-modem
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For full API reference, see the GitHub Pages
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https://jgromes.github.io/RadioLib/
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The SX1276 / 7 / 8 / 9 supports FHSS or Frequency Hopping Spread Spectrum.
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Once a hopping period is set and a transmission is started the radio
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will begin triggering interrupts every hop period where the radio frequency
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is changed to the next channel. This allows a simple mechanism to abide by
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the FCC 400ms max dwell time rule.
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https://www.govinfo.gov/content/pkg/CFR-2019-title47-vol1/pdf/CFR-2019-title47-vol1-sec15-247.pdf
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*/
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#include <RadioLib.h> //Click here to get the library: http://librarymanager/All#RadioLib
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//Pins for RFM97 100mW Shield to SparkFun ESP32 Thing Plus C
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int pin_cs = 15;
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int pin_dio0 = 26;
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int pin_dio1 = 25;
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int pin_rst = 32;
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SX1276 radio = new Module(pin_cs, pin_dio0, pin_rst, pin_dio1);
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int counter = 0;
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volatile bool rxComplete = false;
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volatile bool fhssChange = false;
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//The channel frequencies can be generated randomly or hard coded
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float channels[] = {908.0, 906.0, 907.0, 905.0, 903.0, 910.0, 909.0};
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int numberOfChannels = sizeof(channels) / sizeof(float);
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int hopsCompleted = 0;
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void setup()
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{
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Serial.begin(115200);
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//Begin radio on home channel
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Serial.print(F("[SX127x] Initializing ... "));
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int state = radio.begin(channels[0]);
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if (state != RADIOLIB_ERR_NONE)
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{
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Serial.print(F("Failed with code: "));
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Serial.println(state);
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}
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else
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Serial.println(F("Success!"));
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// Set hop period to enable FHSS
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// We set an artifically short period to show lots of hops
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// HoppingPeriod = Tsym * FreqHoppingPeriod
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// Given defaults of spreadfactor = 9, bandwidth = 125, it follows Tsym = 4.10ms
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// HoppingPeriod = 4.10 * 9 = 36.9ms. Can be as high as 400ms to be within regulatory limits
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radio.setFHSSHoppingPeriod(9);
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Serial.print(F("Hopping period: "));
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Serial.println(radio.getFHSSHoppingPeriod());
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radio.setDio0Action(dio0ISR); //Called when transmission is finished
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radio.setDio1Action(dio1ISR); //Called after a transmission has started, so we can move to next freq
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radio.startReceive();
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Serial.println(F("Waiting for new packet"));
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}
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void loop()
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{
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if (rxComplete == true)
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{
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uint8_t incomingBuffer[255];
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radio.readData(incomingBuffer, 255);
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uint8_t receivedBytes = radio.getPacketLength();
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Serial.write(incomingBuffer, receivedBytes);
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Serial.println();
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Serial.print(F("Hops completed: "));
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Serial.println(hopsCompleted);
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hopsCompleted = 0;
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radio.startReceive();
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rxComplete = false;
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}
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if (fhssChange == true)
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{
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radio.setFrequency(channels[radio.getFHSSChannel() % numberOfChannels]);
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//Serial.print(F("Radio on channel: "));
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//Serial.println(radio.getFHSSChannel());
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hopsCompleted++;
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radio.clearFHSSInt();
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fhssChange = false;
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}
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}
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//ISR when DIO0 goes low
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//Called when transmission is complete or when RX is received
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void dio0ISR(void)
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{
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rxComplete = true;
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}
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//ISR when DIO1 goes low
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//Called when FhssChangeChannel interrupt occurs (at the beginning of each transmission)
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void dio1ISR(void)
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{
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fhssChange = true;
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}
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