firmware/src/MeshRadio.cpp

#include <SPI.h>
#include "RH_RF95.h"
#include <RHMesh.h>
#include <assert.h>

#include <pb_encode.h>
#include <pb_decode.h>
#include "MeshRadio.h"
#include "configuration.h"
#include "NodeDB.h"

#define DEFAULT_CHANNEL_NUM 3 // we randomly pick one

/// 16 bytes of random PSK for our _public_ default channel that all devices power up on
static const uint8_t defaultpsk[] = {0xd4, 0xf1, 0xbb, 0x3a, 0x20, 0x29, 0x07, 0x59, 0xf0, 0xbc, 0xff, 0xab, 0xcf, 0x4e, 0x69, 0xbf};

/**
 * ## LoRaWAN for North America

LoRaWAN defines 64, 125 kHz channels from 902.3 to 914.9 MHz increments.

The maximum output power for North America is +30 dBM.

The band is from 902 to 928 MHz. It mentions channel number and its respective channel frequency. All the 13 channels are separated by 2.16 MHz with respect to the adjacent channels.  
Channel zero starts at 903.08 MHz center frequency.
*/

MeshRadio::MeshRadio(MemoryPool<MeshPacket> &_pool, PointerQueue<MeshPacket> &_rxDest)
    : rf95(_pool, _rxDest),
      manager(rf95)
{
  myNodeInfo.num_channels = NUM_CHANNELS;

  //radioConfig.modem_config = RadioConfig_ModemConfig_Bw125Cr45Sf128;  // medium range and fast
  //channelSettings.modem_config = ChannelSettings_ModemConfig_Bw500Cr45Sf128;  // short range and fast, but wide bandwidth so incompatible radios can talk together
  channelSettings.modem_config = ChannelSettings_ModemConfig_Bw125Cr48Sf4096; // slow and long range

  channelSettings.tx_power = 23;
  channelSettings.channel_num = DEFAULT_CHANNEL_NUM;
  memcpy(&channelSettings.psk, &defaultpsk, sizeof(channelSettings.psk));
  strcpy(channelSettings.name, "Default");
  // Can't print strings this early - serial not setup yet
  // DEBUG_MSG("Set meshradio defaults name=%s\n", channelSettings.name);
}

bool MeshRadio::init()
{
  DEBUG_MSG("Starting meshradio init...\n");

#ifdef RESET_GPIO
  pinMode(RESET_GPIO, OUTPUT); // Deassert reset
  digitalWrite(RESET_GPIO, HIGH);

  // pulse reset
  digitalWrite(RESET_GPIO, LOW);
  delay(10);
  digitalWrite(RESET_GPIO, HIGH);
  delay(10);
#endif

  manager.setThisAddress(nodeDB.getNodeNum()); // Note: we must do this here, because the nodenum isn't inited at constructor time.

  if (!manager.init())
  {
    DEBUG_MSG("LoRa radio init failed\n");
    DEBUG_MSG("Uncomment '#define SERIAL_DEBUG' in RH_RF95.cpp for detailed debug info\n");
    return false;
  }

  // not needed - defaults on
  // rf95.setPayloadCRC(true);

  reloadConfig();

  return true;
}

void MeshRadio::reloadConfig()
{
  rf95.setModeIdle(); // Need to be idle before doing init

  // Set up default configuration
  // No Sync Words in LORA mode.
  rf95.setModemConfig((RH_RF95::ModemConfigChoice)channelSettings.modem_config); // Radio default
                                                                                 //    setModemConfig(Bw125Cr48Sf4096); // slow and reliable?
  // rf95.setPreambleLength(8);           // Default is 8

  assert(channelSettings.channel_num < NUM_CHANNELS); // If the phone tries to tell us to use an illegal channel then panic

  // Defaults after init are 434.0MHz, modulation GFSK_Rb250Fd250, +13dbM
  float center_freq = CH0 + CH_SPACING * channelSettings.channel_num;
  if (!rf95.setFrequency(center_freq))
  {
    DEBUG_MSG("setFrequency failed\n");
    assert(0); // fixme panic
  }

  // Defaults after init are 434.0MHz, 13dBm, Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on

  // The default transmitter power is 13dBm, using PA_BOOST.
  // If you are using RFM95/96/97/98 modules which uses the PA_BOOST transmitter pin, then
  // you can set transmitter powers from 5 to 23 dBm:
  // FIXME - can we do this?  It seems to be in the Heltec board.
  rf95.setTxPower(channelSettings.tx_power, false);

  DEBUG_MSG("Set radio: name=%s. config=%u, ch=%d, txpower=%d\n", channelSettings.name, channelSettings.modem_config, channelSettings.channel_num, channelSettings.tx_power);

  // Done with init tell radio to start receiving
  rf95.setModeRx();
}


ErrorCode MeshRadio::send(MeshPacket *p)
{
  return rf95.send(p);
}



void MeshRadio::loop()
{
  // Currently does nothing, since we do it all in ISRs now
}