163 lines
5.0 KiB
C++
163 lines
5.0 KiB
C++
/*******************************************************************************
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* Copyright (c) 2015 Matthijs Kooijman
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*
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* Permission is hereby granted, free of charge, to anyone
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* obtaining a copy of this document and accompanying files,
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* to do whatever they want with them without any restriction,
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* including, but not limited to, copying, modification and redistribution.
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* NO WARRANTY OF ANY KIND IS PROVIDED.
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*
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* This example transmits data on hardcoded channel and receives data
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* when not transmitting. Running this sketch on two nodes should allow
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* them to communicate.
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*******************************************************************************/
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#include <lmic.h>
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#include <hal/hal.h>
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#include <SPI.h>
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#if !defined(DISABLE_INVERT_IQ_ON_RX)
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#error This example requires DISABLE_INVERT_IQ_ON_RX to be set. Update \
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config.h in the lmic library to set it.
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#endif
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// How often to send a packet. Note that this sketch bypasses the normal
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// LMIC duty cycle limiting, so when you change anything in this sketch
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// (payload length, frequency, spreading factor), be sure to check if
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// this interval should not also be increased.
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// See this spreadsheet for an easy airtime and duty cycle calculator:
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// https://docs.google.com/spreadsheets/d/1voGAtQAjC1qBmaVuP1ApNKs1ekgUjavHuVQIXyYSvNc
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#define TX_INTERVAL 2000
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// Pin mapping
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const lmic_pinmap lmic_pins = {
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.nss = 6,
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.rxtx = LMIC_UNUSED_PIN,
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.rst = 5,
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.dio = {2, 3, 4},
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};
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// These callbacks are only used in over-the-air activation, so they are
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// left empty here (we cannot leave them out completely unless
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// DISABLE_JOIN is set in config.h, otherwise the linker will complain).
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void os_getArtEui (u1_t* buf) { }
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void os_getDevEui (u1_t* buf) { }
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void os_getDevKey (u1_t* buf) { }
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void onEvent (ev_t ev) {
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}
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osjob_t txjob;
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osjob_t timeoutjob;
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static void tx_func (osjob_t* job);
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// Transmit the given string and call the given function afterwards
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void tx(const char *str, osjobcb_t func) {
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os_radio(RADIO_RST); // Stop RX first
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delay(1); // Wait a bit, without this os_radio below asserts, apparently because the state hasn't changed yet
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LMIC.dataLen = 0;
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while (*str)
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LMIC.frame[LMIC.dataLen++] = *str++;
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LMIC.osjob.func = func;
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os_radio(RADIO_TX);
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Serial.println("TX");
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}
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// Enable rx mode and call func when a packet is received
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void rx(osjobcb_t func) {
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LMIC.osjob.func = func;
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LMIC.rxtime = os_getTime(); // RX _now_
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// Enable "continuous" RX (e.g. without a timeout, still stops after
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// receiving a packet)
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os_radio(RADIO_RXON);
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Serial.println("RX");
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}
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static void rxtimeout_func(osjob_t *job) {
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digitalWrite(LED_BUILTIN, LOW); // off
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}
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static void rx_func (osjob_t* job) {
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// Blink once to confirm reception and then keep the led on
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digitalWrite(LED_BUILTIN, LOW); // off
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delay(10);
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digitalWrite(LED_BUILTIN, HIGH); // on
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// Timeout RX (i.e. update led status) after 3 periods without RX
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os_setTimedCallback(&timeoutjob, os_getTime() + ms2osticks(3*TX_INTERVAL), rxtimeout_func);
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// Reschedule TX so that it should not collide with the other side's
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// next TX
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os_setTimedCallback(&txjob, os_getTime() + ms2osticks(TX_INTERVAL/2), tx_func);
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Serial.print("Got ");
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Serial.print(LMIC.dataLen);
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Serial.println(" bytes");
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Serial.write(LMIC.frame, LMIC.dataLen);
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Serial.println();
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// Restart RX
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rx(rx_func);
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}
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static void txdone_func (osjob_t* job) {
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rx(rx_func);
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}
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// log text to USART and toggle LED
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static void tx_func (osjob_t* job) {
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// say hello
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tx("Hello, world!", txdone_func);
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// reschedule job every TX_INTERVAL (plus a bit of random to prevent
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// systematic collisions), unless packets are received, then rx_func
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// will reschedule at half this time.
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os_setTimedCallback(job, os_getTime() + ms2osticks(TX_INTERVAL + random(500)), tx_func);
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}
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// application entry point
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void setup() {
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Serial.begin(115200);
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Serial.println("Starting");
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#ifdef VCC_ENABLE
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// For Pinoccio Scout boards
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pinMode(VCC_ENABLE, OUTPUT);
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digitalWrite(VCC_ENABLE, HIGH);
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delay(1000);
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#endif
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pinMode(LED_BUILTIN, OUTPUT);
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// initialize runtime env
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os_init();
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// Set up these settings once, and use them for both TX and RX
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#if defined(CFG_eu868)
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// Use a frequency in the g3 which allows 10% duty cycling.
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LMIC.freq = 869525000;
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#elif defined(CFG_us915)
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LMIC.freq = 902300000;
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#endif
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// Maximum TX power
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LMIC.txpow = 27;
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// Use a medium spread factor. This can be increased up to SF12 for
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// better range, but then the interval should be (significantly)
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// lowered to comply with duty cycle limits as well.
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LMIC.datarate = DR_SF9;
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// This sets CR 4/5, BW125 (except for DR_SF7B, which uses BW250)
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LMIC.rps = updr2rps(LMIC.datarate);
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Serial.println("Started");
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Serial.flush();
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// setup initial job
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os_setCallback(&txjob, tx_func);
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}
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void loop() {
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// execute scheduled jobs and events
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os_runloop_once();
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}
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