Initial import of the main code from https://github.com/slepp/AX25
Partially functional, but no accuracy tests complete yet.
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#include <Arduino.h>
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#include "HamShield.h"
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#include "SimpleFIFO.h"
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#include <util/atomic.h>
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#define PHASE_BIT 8
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#define PHASE_INC 1
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#define PHASE_MAX (SAMPLEPERBIT * PHASE_BIT)
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#define PHASE_THRES (PHASE_MAX / 2)
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#define BIT_DIFFER(bitline1, bitline2) (((bitline1) ^ (bitline2)) & 0x01)
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#define EDGE_FOUND(bitline)            BIT_DIFFER((bitline), (bitline) >> 1)
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#define PPOOL_SIZE 2
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#define ACCUMULATOR_BITS 24 // This is 2^10 bits used from accum
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//#undef PROGMEM
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//#define PROGMEM __attribute__((section(".progmem.data")))
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const uint8_t PROGMEM sinetable[256] = {
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  128,131,134,137,140,143,146,149,152,156,159,162,165,168,171,174,
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  176,179,182,185,188,191,193,196,199,201,204,206,209,211,213,216,
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  218,220,222,224,226,228,230,232,234,236,237,239,240,242,243,245,
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  246,247,248,249,250,251,252,252,253,254,254,255,255,255,255,255,
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  255,255,255,255,255,255,254,254,253,252,252,251,250,249,248,247,
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  246,245,243,242,240,239,237,236,234,232,230,228,226,224,222,220,
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  218,216,213,211,209,206,204,201,199,196,193,191,188,185,182,179,
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  176,174,171,168,165,162,159,156,152,149,146,143,140,137,134,131,
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  128,124,121,118,115,112,109,106,103,99, 96, 93, 90, 87, 84, 81, 
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  79, 76, 73, 70, 67, 64, 62, 59, 56, 54, 51, 49, 46, 44, 42, 39, 
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  37, 35, 33, 31, 29, 27, 25, 23, 21, 19, 18, 16, 15, 13, 12, 10, 
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  9,  8,  7,  6,  5,  4,  3,  3,  2,  1,  1,  0,  0,  0,  0,  0,  
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  0,  0,  0,  0,  0,  0,  1,  1,  2,  3,  3,  4,  5,  6,  7,  8,  
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  9,  10, 12, 13, 15, 16, 18, 19, 21, 23, 25, 27, 29, 31, 33, 35, 
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  37, 39, 42, 44, 46, 49, 51, 54, 56, 59, 62, 64, 67, 70, 73, 76, 
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  79, 81, 84, 87, 90, 93, 96, 99, 103,106,109,112,115,118,121,124
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};
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#define AFSK_SPACE 0
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#define AFSK_MARK  1
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// Timers
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volatile unsigned long lastTx = 0;
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volatile unsigned long lastTxEnd = 0;
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volatile unsigned long lastRx = 0;
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#define REFCLK 9600
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//#define REFCLK 31372.54902
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//#define REFCLK (16000000.0/510.0)
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//#define REFCLK 31200.0
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// 2200Hz = pow(2,32)*2200.0/refclk
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// 1200Hz = pow(2,32)*1200.0/refclk
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static const unsigned long toneStep[2] = {
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  pow(2,32)*2200.0/REFCLK,
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  pow(2,32)*1200.0/REFCLK
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};
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// Set to an arbitrary frequency
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void AFSK::Encoder::setFreq(unsigned long freq, byte vol) {
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  unsigned long newStep = pow(2,32)*freq/REFCLK;
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  rStep = newStep; // Atomic? (ish)
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}
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// This allows a programmatic way to tune the output tones
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static const byte toneVolume[2] = {
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  255,
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  255
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};
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#define T_BIT ((unsigned int)(REFCLK/1200))
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void AFSK::Encoder::process() {
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  // Check what clock pulse we're on
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  if(bitClock == 0) { // We are onto our next bit timing  
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    // We're on the start of a byte position, so fetch one
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    if(bitPosition == 0) {
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      if(preamble) { // Still in preamble
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        currentByte = HDLC_PREAMBLE;
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        --preamble; // Decrement by one
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      } else {
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        if(!packet) { // We aren't on a packet, grab one
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          // Unless we already sent enough
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          if(maxTx-- == 0) {
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            stop();
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            lastTxEnd = millis();
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            return;
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          }
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          packet = pBuf.getPacket();
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          if(!packet) { // There actually weren't any
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            stop(); // Stop transmitting and return
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            lastTxEnd = millis();
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            return;
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          }
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        lastTx = millis();
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        currentBytePos = 0;
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      }
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      // We ran out of actual data, provide an HDLC frame (idle)
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      if(currentBytePos++ == packet->len) {
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        pBuf.freePacket(packet);
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        packet = pBuf.getPacket(); // Get the next, if any
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        currentBytePos = 0;
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        currentByte = HDLC_FRAME;
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        hdlc = true;
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      } else {
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        // Grab the next byte
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        currentByte = packet->getByte(); //[currentBytePos++];
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        if(currentByte == HDLC_ESCAPE) {
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          currentByte = packet->getByte(); //[currentBytePos++];
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          hdlc = true;
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        } else {
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          hdlc = false;
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        }
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      }
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    }
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  }
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  // Pickup the last bit
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  currentBit = currentByte & 0x1;    
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  if(lastZero == 5) {
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    currentBit = 0; // Force a 0 bit output
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  } else {
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    currentByte >>= 1; // Bit shift it right, for the next round
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    ++bitPosition; // Note our increase in position
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  }
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  // To handle NRZI 5 bit stuffing, count the bits
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  if(!currentBit || hdlc)
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    lastZero = 0;
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  else
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    ++lastZero;
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  // NRZI and AFSK uses toggling 0s, "no change" on 1
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  // So, if not a 1, toggle to the opposite tone
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  if(!currentBit)
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    currentTone = !currentTone;
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  }
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  // Advance the bitclock here, to let first bit be sent early 
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  if(++bitClock == T_BIT)
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    bitClock = 0;
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  accumulator += toneStep[currentTone];
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  uint8_t phAng = (accumulator >> ACCUMULATOR_BITS);
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  /*if(toneVolume[currentTone] != 255) {
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  OCR2B = pwm * toneVolume[currentTone] / 255;
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  } else {*/
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  // No volume scaling required
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  OCR2B = pgm_read_byte_near(sinetable + phAng);
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  /*}*/
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}
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bool AFSK::Encoder::start() {
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  if(!done || sending) {
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    return false;
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  }
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  if(randomWait > millis()) {
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    return false;
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  }
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  accumulator = 0;
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  // First real byte is a frame
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  currentBit = 0;
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  lastZero = 0;
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  bitPosition = 0;
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  bitClock = 0;
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  preamble = 23; // 6.7ms each, 23 = 153ms
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  done = false;
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  hdlc = true;
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  packet = 0x0; // No initial packet, find in the ISR
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  currentBytePos = 0;
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  maxTx = 3;
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  sending = true;
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  return true;
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}
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void AFSK::Encoder::stop() {
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  randomWait = 0;
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  sending = false;
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  done = true;
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  OCR2B = 0;
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}
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AFSK::Decoder::Decoder() {
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  // Initialize the sampler delay line (phase shift)
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  for(unsigned char i = 0; i < SAMPLEPERBIT/2; i++)
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  delay_fifo.enqueue(0);
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}
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bool AFSK::HDLCDecode::hdlcParse(bool bit, SimpleFIFO<uint8_t,HAMSHIELD_AFSK_RX_FIFO_LEN> *fifo) {
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  bool ret = true;
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  demod_bits <<= 1;
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  demod_bits |= bit ? 1 : 0;
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  // Flag
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  if(demod_bits == HDLC_FRAME) {
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    fifo->enqueue(HDLC_FRAME);
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    rxstart = true;
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    currchar = 0;
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    bit_idx = 0;
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    return ret;
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  }
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  // Reset
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  if((demod_bits & HDLC_RESET) == HDLC_RESET) {
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    rxstart = false;
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    lastRx = millis();
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    return ret;
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  }
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  if(!rxstart) {
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    return ret;
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  }
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  // Stuffed?
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  if((demod_bits & 0x3f) == 0x3e)
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    return ret;
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  if(demod_bits & 0x01)
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    currchar |= 0x80;
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  if(++bit_idx >= 8) {
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    if(currchar == HDLC_FRAME ||
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      currchar == HDLC_RESET ||
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      currchar == HDLC_ESCAPE) {
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        fifo->enqueue(HDLC_ESCAPE);
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      }
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    fifo->enqueue(currchar & 0xff);
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    currchar = 0;
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    bit_idx = 0;
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  } else {
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    currchar >>= 1;
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  }  
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  return ret;
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}
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// Handle the A/D converter interrupt (hopefully quickly :)
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void AFSK::Decoder::process(int8_t curr_sample) {
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  // Run the same through the phase multiplier and butterworth filter
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  iir_x[0] = iir_x[1];
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  iir_x[1] = ((int8_t)delay_fifo.dequeue() * curr_sample) >> 2;
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  iir_y[0] = iir_y[1];
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  iir_y[1] = iir_x[0] + iir_x[1] + (iir_y[0] >> 1) + (iir_y[0]>>3) + (iir_y[0]>>5);
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  // Shift the bit into place based on the output of the discriminator
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  sampled_bits <<= 1;
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  sampled_bits |= (iir_y[1] > 0) ? 1 : 0;
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  // Place this ADC sample into the delay line
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  delay_fifo.enqueue(curr_sample);
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  // If we found a 0/1 transition, adjust phases to track
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  if(EDGE_FOUND(sampled_bits)) {
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    if(curr_phase < PHASE_THRES)
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      curr_phase += PHASE_INC;
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    else
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      curr_phase -= PHASE_INC;
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  }
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  // Move ahead in phase
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  curr_phase += PHASE_BIT;
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  // If we've gone over the phase maximum, we should now have some data
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  if(curr_phase >= PHASE_MAX) {
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    curr_phase %= PHASE_MAX;
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    found_bits <<= 1;
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    // If we have 3 bits or more set, it's a positive bit
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    register uint8_t bits = sampled_bits & 0x07;
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    if(bits == 0x07 || bits == 0x06 || bits == 0x05 || bits == 0x03) {
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      found_bits |= 1;
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    }
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    hdlc.hdlcParse(!EDGE_FOUND(found_bits), &rx_fifo); // Process it
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  }
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}
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// This routine uses a pre-allocated Packet structure
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// to save on the memory requirements of the stream data
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bool AFSK::Decoder::read() {
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  bool retVal = false;
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  if(!currentPacket) { // We failed a prior memory allocation
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    currentPacket = pBuf.makePacket(PACKET_MAX_LEN);
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    if(!currentPacket) // Still nothing
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      return false;
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  }
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  // While we have AFSK receive FIFO bytes...
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  while(rx_fifo.count()) {
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    // Grab the character
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    char c = rx_fifo.dequeue();
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    bool escaped = false;
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    if(c == HDLC_ESCAPE) { // We received an escaped byte, mark it
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      escaped = true;
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      currentPacket->append(HDLC_ESCAPE); // Append without FCS
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      c = rx_fifo.dequeue(); // Reset to the next character
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    }
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    // Append all the bytes
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    // This will include unescaped HDLC_FRAME bytes
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    //if(c == HDLC_FRAME && !escaped)
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    //currentPacket->append(c); // Framing bytes don't get FCS updates
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    //else
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    if(c != HDLC_FRAME)
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      currentPacket->appendFCS(c); // Escaped characters and all else go into FCS
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    if(currentPacket->len > PACKET_MAX_LEN) {
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      // We've now gone too far and picked up far too many bytes
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      // Cancel this frame, start back at the beginning
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      currentPacket->clear();
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      continue;
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    }
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    // We have a frame boundary, if it isn't escaped
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    // If it's escaped, it was part of the data stream
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    if(c == HDLC_FRAME && !escaped) {
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      if(!currentPacket->len) {
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        currentPacket->clear(); // There wasn't any data, restart stream
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        continue;
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      } else {
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        // We have some bytes in stream, check it meets minimum payload length
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        // Min payload is 1 (flag) + 14 (addressing) + 2 (control/PID) + 1 (flag)
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        if(currentPacket->len >= 16) {          
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          // We should end up here with a valid FCS due to the appendFCS
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          if(currentPacket->crcOK()) { // Magic number for the CRC check passing
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            // Valid frame, so, let's filter for control + PID
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            // Maximum search distance is 71 bytes to end of the address fields
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            // Skip the HDLC frame start
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            bool filtered = false;
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		||||
            for(unsigned char i = 0; i < (currentPacket->len<70?currentPacket->len:71); ++i) {
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		||||
              if((currentPacket->getByte() & 0x1) == 0x1) { // Found a byte with LSB set
 | 
			
		||||
                // which marks the final address payload
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                // next two bytes should be the control/PID
 | 
			
		||||
                if(currentPacket->getByte() == 0x03 && currentPacket->getByte() == 0xf0) {
 | 
			
		||||
                  filtered = true;
 | 
			
		||||
                  break; // Found it
 | 
			
		||||
                }
 | 
			
		||||
              }
 | 
			
		||||
            }
 | 
			
		||||
            
 | 
			
		||||
            if(!filtered) {
 | 
			
		||||
              // Frame wasn't one we care about, discard
 | 
			
		||||
              currentPacket->clear();
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		||||
              continue;
 | 
			
		||||
            }
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		||||
            
 | 
			
		||||
            // It's all done and formatted, ready to go
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		||||
            currentPacket->ready = 1;
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		||||
            if(!pBuf.putPacket(currentPacket)) // Put it in the receive FIFO
 | 
			
		||||
              pBuf.freePacket(currentPacket); // Out of FIFO space, so toss it
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		||||
            
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		||||
            // Allocate a new one of maximum length
 | 
			
		||||
            currentPacket = pBuf.makePacket(PACKET_MAX_LEN);
 | 
			
		||||
            retVal = true;
 | 
			
		||||
          }
 | 
			
		||||
        }
 | 
			
		||||
      }
 | 
			
		||||
      // Restart the stream
 | 
			
		||||
      currentPacket->clear();
 | 
			
		||||
    }
 | 
			
		||||
  }
 | 
			
		||||
  return retVal; // This is true if we parsed a packet in this flow
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
void AFSK::Decoder::start() {
 | 
			
		||||
  // Do this in start to allocate our first packet
 | 
			
		||||
  currentPacket = pBuf.makePacket(PACKET_MAX_LEN);
 | 
			
		||||
  // Configure the ADC and Timer1 to trigger automatic interrupts
 | 
			
		||||
  TCCR1A = 0;
 | 
			
		||||
  TCCR1B = _BV(CS11) | _BV(WGM13) | _BV(WGM12);
 | 
			
		||||
  ICR1 = ((F_CPU / 8) / REFCLK) - 1;
 | 
			
		||||
  ADMUX = _BV(REFS0) | _BV(ADLAR) | 0; // Channel 0, shift result left (ADCH used)
 | 
			
		||||
  DDRC &= ~_BV(0);
 | 
			
		||||
  PORTC &= ~_BV(0);
 | 
			
		||||
  DIDR0 |= _BV(0);
 | 
			
		||||
  ADCSRB = _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0);
 | 
			
		||||
  ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2); // | _BV(ADPS0);  
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
AFSK::PacketBuffer::PacketBuffer() {
 | 
			
		||||
  nextPacketIn = 0;
 | 
			
		||||
  nextPacketOut = 0;
 | 
			
		||||
  inBuffer = 0;
 | 
			
		||||
  for(unsigned char i = 0; i < PACKET_BUFFER_SIZE; ++i) {
 | 
			
		||||
    packets[i] = 0x0;
 | 
			
		||||
  }
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
unsigned char AFSK::PacketBuffer::readyCount() volatile {
 | 
			
		||||
  unsigned char i;
 | 
			
		||||
  unsigned int cnt = 0;
 | 
			
		||||
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 | 
			
		||||
    for(i = 0; i < PACKET_BUFFER_SIZE; ++i) {
 | 
			
		||||
      if(packets[i] && packets[i]->ready)
 | 
			
		||||
        ++cnt;
 | 
			
		||||
    }
 | 
			
		||||
  }  
 | 
			
		||||
  return cnt;
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Return NULL on empty packet buffers
 | 
			
		||||
AFSK::Packet *AFSK::PacketBuffer::getPacket() volatile {
 | 
			
		||||
  unsigned char i = 0;
 | 
			
		||||
  AFSK::Packet *p = NULL;
 | 
			
		||||
  
 | 
			
		||||
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 | 
			
		||||
    if(inBuffer == 0) {
 | 
			
		||||
      return 0x0;
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    do {
 | 
			
		||||
      p = packets[nextPacketOut];
 | 
			
		||||
      if(p) {
 | 
			
		||||
        packets[nextPacketOut] = 0x0;
 | 
			
		||||
        --inBuffer;
 | 
			
		||||
      }
 | 
			
		||||
      nextPacketOut = ++nextPacketOut % PACKET_BUFFER_SIZE;
 | 
			
		||||
      ++i;
 | 
			
		||||
    } while(!p && i<PACKET_BUFFER_SIZE);
 | 
			
		||||
    
 | 
			
		||||
    // Return whatever we found, if anything
 | 
			
		||||
  }  
 | 
			
		||||
  return p;
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
//void Packet::init(uint8_t *buf, unsigned int dlen, bool freeData) {
 | 
			
		||||
void AFSK::Packet::init(unsigned short dlen) {
 | 
			
		||||
  //data = (unsigned char *)buf;
 | 
			
		||||
  ready = 0;
 | 
			
		||||
  freeData = 1; //freeData;
 | 
			
		||||
  type = PACKET_STATIC;
 | 
			
		||||
  len = 0; // We had a length, but don't put it here.
 | 
			
		||||
  maxLen = dlen; // Put it here instead
 | 
			
		||||
  dataPtr = (uint8_t *)malloc(dlen+16);
 | 
			
		||||
  dataPos = dataPtr;
 | 
			
		||||
  readPos = dataPtr;
 | 
			
		||||
  fcs = 0xffff;
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Allocate a new packet with a data buffer as set
 | 
			
		||||
AFSK::Packet *AFSK::PacketBuffer::makePacket(unsigned short dlen) {
 | 
			
		||||
  AFSK::Packet *p;
 | 
			
		||||
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 | 
			
		||||
    //Packet *p = findPooledPacket();
 | 
			
		||||
    p = new Packet(); //(Packet *)malloc(sizeof(Packet));
 | 
			
		||||
    if(p) // If allocated
 | 
			
		||||
      p->init(dlen);
 | 
			
		||||
  }
 | 
			
		||||
  return p; // Passes through a null on failure.
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Free a packet struct, mainly convenience
 | 
			
		||||
void AFSK::PacketBuffer::freePacket(Packet *p) {
 | 
			
		||||
  if(!p)
 | 
			
		||||
  return;
 | 
			
		||||
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 | 
			
		||||
    p->free();
 | 
			
		||||
    /*unsigned char i;
 | 
			
		||||
    for(i = 0; i < PPOOL_SIZE; ++i)
 | 
			
		||||
    if(p == &(pPool[i]))
 | 
			
		||||
    break;
 | 
			
		||||
    if(i < PPOOL_SIZE)
 | 
			
		||||
    pStatus &= ~(1<<i);*/
 | 
			
		||||
    delete p;
 | 
			
		||||
  }  
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Put a packet onto the buffer array
 | 
			
		||||
bool AFSK::PacketBuffer::putPacket(Packet *p) volatile {
 | 
			
		||||
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 | 
			
		||||
    if(inBuffer >= PACKET_BUFFER_SIZE) {
 | 
			
		||||
      return false;
 | 
			
		||||
    }
 | 
			
		||||
    packets[nextPacketIn] = p;
 | 
			
		||||
    nextPacketIn = ++nextPacketIn % PACKET_BUFFER_SIZE;
 | 
			
		||||
    ++inBuffer;
 | 
			
		||||
  }  
 | 
			
		||||
  return true;
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Print a single byte to the data array
 | 
			
		||||
size_t AFSK::Packet::write(uint8_t c) {
 | 
			
		||||
  return (appendFCS(c)?1:0);
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
size_t AFSK::Packet::write(const uint8_t *ptr, size_t len) {
 | 
			
		||||
  size_t i;
 | 
			
		||||
  for(i = 0; i < len; ++i)
 | 
			
		||||
    if(!appendFCS(ptr[i]))
 | 
			
		||||
      break;
 | 
			
		||||
  return i;
 | 
			
		||||
}
 | 
			
		||||
  
 | 
			
		||||
// Determine what we want to do on this ADC tick.
 | 
			
		||||
void AFSK::timer() {
 | 
			
		||||
  if(encoder.isSending())
 | 
			
		||||
    encoder.process();
 | 
			
		||||
  decoder.process(ADCH - 128);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void AFSK::start() {
 | 
			
		||||
  afskEnabled = true;
 | 
			
		||||
  decoder.start();
 | 
			
		||||
}
 | 
			
		||||
| 
						 | 
				
			
			@ -0,0 +1,265 @@
 | 
			
		|||
#ifndef _AFSK_H_
 | 
			
		||||
#define _AFSK_H_
 | 
			
		||||
 | 
			
		||||
#include <Arduino.h>
 | 
			
		||||
#include <SimpleFIFO.h>
 | 
			
		||||
 | 
			
		||||
#define SAMPLERATE 9600
 | 
			
		||||
#define BITRATE    1200
 | 
			
		||||
 | 
			
		||||
#define SAMPLEPERBIT (SAMPLERATE / BITRATE)
 | 
			
		||||
 | 
			
		||||
#define RX_FIFO_LEN 16
 | 
			
		||||
 | 
			
		||||
#define PACKET_BUFFER_SIZE 2
 | 
			
		||||
#define PACKET_STATIC 0
 | 
			
		||||
 | 
			
		||||
// This is with all the digis, two addresses, framing and full payload
 | 
			
		||||
// Two more bytes are added for HDLC_ESCAPEs
 | 
			
		||||
#define PACKET_MAX_LEN 512
 | 
			
		||||
 | 
			
		||||
// HDLC framing bits
 | 
			
		||||
#define HDLC_FRAME    0x7E
 | 
			
		||||
#define HDLC_RESET    0x7F
 | 
			
		||||
#define HDLC_PREAMBLE 0x00
 | 
			
		||||
#define HDLC_ESCAPE   0x1B
 | 
			
		||||
#define HDLC_TAIL     0x1C
 | 
			
		||||
 | 
			
		||||
class AFSK {
 | 
			
		||||
private:
 | 
			
		||||
  volatile bool afskEnabled;
 | 
			
		||||
public:
 | 
			
		||||
  bool enabled() { return afskEnabled; };
 | 
			
		||||
  
 | 
			
		||||
  class Packet:public Print {
 | 
			
		||||
  public:
 | 
			
		||||
    Packet():Print() {};
 | 
			
		||||
    virtual size_t write(uint8_t);
 | 
			
		||||
    // Stock virtual method does what we want here.
 | 
			
		||||
    //virtual size_t write(const char *);
 | 
			
		||||
    virtual size_t write(const uint8_t *, size_t);
 | 
			
		||||
    using Print::write;
 | 
			
		||||
    unsigned char ready : 1;
 | 
			
		||||
    unsigned char type : 2;
 | 
			
		||||
    unsigned char freeData : 1;
 | 
			
		||||
    unsigned short len;
 | 
			
		||||
    unsigned short maxLen;
 | 
			
		||||
    //void init(uint8_t *buf, unsigned int dlen, bool freeData); 
 | 
			
		||||
    void init(unsigned short dlen);
 | 
			
		||||
    inline void free() {
 | 
			
		||||
      if(freeData)
 | 
			
		||||
      ::free(dataPtr);
 | 
			
		||||
    }
 | 
			
		||||
    inline const unsigned char getByte(void) {
 | 
			
		||||
      return *readPos++;
 | 
			
		||||
    }
 | 
			
		||||
    inline const unsigned char getByte(uint16_t p) {
 | 
			
		||||
      return *(dataPtr+p);
 | 
			
		||||
    }
 | 
			
		||||
    inline void start() {
 | 
			
		||||
      fcs = 0xffff;
 | 
			
		||||
      *dataPos++ = HDLC_ESCAPE;
 | 
			
		||||
      *dataPos++ = HDLC_FRAME;
 | 
			
		||||
      len = 2;
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    inline bool append(char c) {
 | 
			
		||||
      if(len < maxLen) {
 | 
			
		||||
        ++len;
 | 
			
		||||
        *dataPos++ = c;
 | 
			
		||||
        return true;
 | 
			
		||||
      }
 | 
			
		||||
      return false;	  
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    #define UPDATE_FCS(d) e=fcs^(d); f=e^(e<<4); fcs=(fcs>>8)^(f<<8)^(f<<3)^(f>>4)
 | 
			
		||||
    //#define UPDATE_FCS(d) s=(d)^(fcs>>8); t=s^(s>>4); fcs=(fcs<<8)^t^(t<<5)^(t<<12)
 | 
			
		||||
    inline bool appendFCS(unsigned char c) {
 | 
			
		||||
      register unsigned char e, f;
 | 
			
		||||
      if(len < maxLen - 4) { // Leave room for FCS/HDLC
 | 
			
		||||
        append(c);
 | 
			
		||||
        UPDATE_FCS(c);
 | 
			
		||||
        return true;
 | 
			
		||||
      }
 | 
			
		||||
      return false;
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    inline void finish() {
 | 
			
		||||
      append(~(fcs & 0xff));
 | 
			
		||||
      append(~((fcs>>8) & 0xff));
 | 
			
		||||
      append(HDLC_ESCAPE);
 | 
			
		||||
      append(HDLC_FRAME);
 | 
			
		||||
      ready = 1;
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    inline void clear() {
 | 
			
		||||
      fcs = 0xffff;
 | 
			
		||||
      len = 0;
 | 
			
		||||
      readPos = dataPtr;
 | 
			
		||||
      dataPos = dataPtr;
 | 
			
		||||
    }
 | 
			
		||||
    
 | 
			
		||||
    inline bool crcOK() {
 | 
			
		||||
      return (fcs == 0xF0B8);
 | 
			
		||||
    }
 | 
			
		||||
  private:
 | 
			
		||||
    uint8_t *dataPtr, *dataPos, *readPos;
 | 
			
		||||
    unsigned short fcs;
 | 
			
		||||
  };
 | 
			
		||||
  
 | 
			
		||||
  
 | 
			
		||||
  class PacketBuffer {
 | 
			
		||||
  public:
 | 
			
		||||
    // Initialize the buffers
 | 
			
		||||
    PacketBuffer();
 | 
			
		||||
    // How many packets are in the buffer?
 | 
			
		||||
    unsigned char count() volatile { return inBuffer; };
 | 
			
		||||
    // And how many of those are ready?
 | 
			
		||||
    unsigned char readyCount() volatile;
 | 
			
		||||
    // Retrieve the next packet
 | 
			
		||||
    Packet *getPacket() volatile;
 | 
			
		||||
    // Create a packet structure as needed
 | 
			
		||||
    // This does not place it in the queue
 | 
			
		||||
    static Packet *makePacket(unsigned short);
 | 
			
		||||
    // Conveniently free packet memory
 | 
			
		||||
    static void freePacket(Packet *);
 | 
			
		||||
    // Place a packet into the buffer
 | 
			
		||||
    bool putPacket(Packet *) volatile;
 | 
			
		||||
  private:
 | 
			
		||||
    volatile unsigned char inBuffer;
 | 
			
		||||
    Packet * volatile packets[PACKET_BUFFER_SIZE];
 | 
			
		||||
    volatile unsigned char nextPacketIn;
 | 
			
		||||
    volatile unsigned char nextPacketOut;
 | 
			
		||||
  };
 | 
			
		||||
  
 | 
			
		||||
  class Encoder {
 | 
			
		||||
  public:
 | 
			
		||||
    Encoder() {
 | 
			
		||||
      randomWait = 1000; // At the very begin, wait at least one second
 | 
			
		||||
      sending = false;
 | 
			
		||||
      done = true;
 | 
			
		||||
      packet = 0x0;
 | 
			
		||||
      currentBytePos = 0;
 | 
			
		||||
    }
 | 
			
		||||
    void setFreq(unsigned long, byte);
 | 
			
		||||
    volatile inline bool isSending() volatile { 
 | 
			
		||||
      return sending; 
 | 
			
		||||
    }
 | 
			
		||||
    volatile inline bool isDone() volatile { 
 | 
			
		||||
      return done; 
 | 
			
		||||
    }
 | 
			
		||||
    volatile inline bool hasPackets() volatile { 
 | 
			
		||||
      return (pBuf.count() > 0); 
 | 
			
		||||
    }
 | 
			
		||||
    inline bool putPacket(Packet *packet) {
 | 
			
		||||
      return pBuf.putPacket(packet);
 | 
			
		||||
    }
 | 
			
		||||
    inline void setRandomWait() {
 | 
			
		||||
      randomWait = 250 + (rand() % 1000) + millis();
 | 
			
		||||
    }
 | 
			
		||||
    bool start();
 | 
			
		||||
    void stop();
 | 
			
		||||
    void process();
 | 
			
		||||
  private:
 | 
			
		||||
    volatile bool sending;
 | 
			
		||||
    byte currentByte;
 | 
			
		||||
    byte currentBit : 1;
 | 
			
		||||
    byte currentTone : 1;
 | 
			
		||||
    byte lastZero : 3;
 | 
			
		||||
    byte bitPosition : 3;
 | 
			
		||||
    byte preamble : 6;
 | 
			
		||||
    byte bitClock;
 | 
			
		||||
    bool hdlc;
 | 
			
		||||
    byte maxTx;
 | 
			
		||||
    Packet *packet;
 | 
			
		||||
    PacketBuffer pBuf;
 | 
			
		||||
    unsigned char currentBytePos;
 | 
			
		||||
    volatile unsigned long randomWait;
 | 
			
		||||
    volatile bool done;
 | 
			
		||||
    // Phase accumulator, 32 bits, we'll use ACCUMULATOR_BITS of it
 | 
			
		||||
    unsigned long accumulator;
 | 
			
		||||
    // Current radian step for the accumulator
 | 
			
		||||
    unsigned long rStep;
 | 
			
		||||
  };
 | 
			
		||||
  
 | 
			
		||||
  class HDLCDecode {
 | 
			
		||||
  public:
 | 
			
		||||
    bool hdlcParse(bool, SimpleFIFO<uint8_t,RX_FIFO_LEN> *fifo);
 | 
			
		||||
    volatile bool rxstart;
 | 
			
		||||
  private:
 | 
			
		||||
    uint8_t demod_bits;
 | 
			
		||||
    uint8_t bit_idx;
 | 
			
		||||
    uint8_t currchar;
 | 
			
		||||
  };
 | 
			
		||||
  
 | 
			
		||||
  class Decoder {
 | 
			
		||||
  public:
 | 
			
		||||
    Decoder();
 | 
			
		||||
    void start();
 | 
			
		||||
    bool read();
 | 
			
		||||
    void process(int8_t);
 | 
			
		||||
    inline bool dataAvailable() {
 | 
			
		||||
      return (rx_fifo.count() > 0);
 | 
			
		||||
    }
 | 
			
		||||
    inline uint8_t getByte() {
 | 
			
		||||
      return rx_fifo.dequeue();
 | 
			
		||||
    }
 | 
			
		||||
    inline uint8_t packetCount() volatile {
 | 
			
		||||
      return pBuf.count();
 | 
			
		||||
    }
 | 
			
		||||
    inline Packet *getPacket() {
 | 
			
		||||
      return pBuf.getPacket();
 | 
			
		||||
    }
 | 
			
		||||
    inline bool isReceiving() volatile {
 | 
			
		||||
      return hdlc.rxstart;
 | 
			
		||||
    }
 | 
			
		||||
  private:
 | 
			
		||||
    Packet *currentPacket;
 | 
			
		||||
    SimpleFIFO<int8_t,SAMPLEPERBIT/2+1> delay_fifo;
 | 
			
		||||
    SimpleFIFO<uint8_t,RX_FIFO_LEN> rx_fifo; // This should be drained fairly often
 | 
			
		||||
    int16_t iir_x[2];
 | 
			
		||||
    int16_t iir_y[2];
 | 
			
		||||
    uint8_t sampled_bits;
 | 
			
		||||
    int8_t curr_phase;
 | 
			
		||||
    uint8_t found_bits;
 | 
			
		||||
    PacketBuffer pBuf;
 | 
			
		||||
    HDLCDecode hdlc;
 | 
			
		||||
  };
 | 
			
		||||
  
 | 
			
		||||
public:
 | 
			
		||||
  inline bool read() {
 | 
			
		||||
    return decoder.read();
 | 
			
		||||
  }
 | 
			
		||||
  inline bool txReady() volatile {
 | 
			
		||||
    if(encoder.isDone() && encoder.hasPackets())
 | 
			
		||||
    return true;
 | 
			
		||||
    return false;
 | 
			
		||||
  }
 | 
			
		||||
  inline bool isDone() volatile { return encoder.isDone(); }
 | 
			
		||||
  inline bool txStart() {
 | 
			
		||||
    if(decoder.isReceiving()) {
 | 
			
		||||
      encoder.setRandomWait();
 | 
			
		||||
      return false;
 | 
			
		||||
    } 
 | 
			
		||||
    return encoder.start();
 | 
			
		||||
  }
 | 
			
		||||
  inline bool putTXPacket(Packet *packet) {
 | 
			
		||||
    bool ret = encoder.putPacket(packet);
 | 
			
		||||
    if(!ret) // No room?
 | 
			
		||||
    PacketBuffer::freePacket(packet);
 | 
			
		||||
    return ret;
 | 
			
		||||
  }
 | 
			
		||||
  inline Packet *getRXPacket() {
 | 
			
		||||
    return decoder.getPacket();
 | 
			
		||||
  }
 | 
			
		||||
  inline uint8_t rxPacketCount() volatile {
 | 
			
		||||
    return decoder.packetCount();
 | 
			
		||||
  }
 | 
			
		||||
  //unsigned long lastTx;
 | 
			
		||||
  //unsigned long lastRx;
 | 
			
		||||
  void start();
 | 
			
		||||
  void timer();
 | 
			
		||||
  Encoder encoder;
 | 
			
		||||
  Decoder decoder;
 | 
			
		||||
};
 | 
			
		||||
#endif /* _AFSK_H_ */
 | 
			
		||||
| 
						 | 
				
			
			@ -1352,3 +1352,13 @@ void HamShield::AFSKOut(char buffer[80]) {
 | 
			
		|||
 | 
			
		||||
}
 | 
			
		||||
*/
 | 
			
		||||
 | 
			
		||||
// This is the ADC timer handler. When enabled, we'll see what we're supposed
 | 
			
		||||
// to be reading/handling, and trigger those on the main object.
 | 
			
		||||
ISR(ADC_vect) {
 | 
			
		||||
  TIFR1 = _BV(ICF1); // Clear the timer flag
 | 
			
		||||
 | 
			
		||||
  if(HamShield::sHamShield->afsk.enabled()) {
 | 
			
		||||
    HamShield::sHamShield->afsk.timer();
 | 
			
		||||
  }
 | 
			
		||||
}
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
							
								
								
									
										18
									
								
								HamShield.h
								
								
								
								
							
							
						
						
									
										18
									
								
								HamShield.h
								
								
								
								
							| 
						 | 
				
			
			@ -9,6 +9,8 @@
 | 
			
		|||
#define _HAMSHIELD_H_
 | 
			
		||||
 | 
			
		||||
#include "I2Cdev_rda.h"
 | 
			
		||||
#include "SimpleFIFO.h"
 | 
			
		||||
#include "AFSK.h"
 | 
			
		||||
#include <avr/pgmspace.h>
 | 
			
		||||
 | 
			
		||||
// HamShield constants
 | 
			
		||||
| 
						 | 
				
			
			@ -19,6 +21,8 @@
 | 
			
		|||
#define HAMSHIELD_PWM_PIN                 11    // Pin assignment for PWM output
 | 
			
		||||
#define HAMSHIELD_EMPTY_CHANNEL_RSSI   -110    // Default threshold where channel is considered "clear"
 | 
			
		||||
 | 
			
		||||
#define HAMSHIELD_AFSK_RX_FIFO_LEN 16
 | 
			
		||||
 | 
			
		||||
// button modes
 | 
			
		||||
#define PTT_MODE 1
 | 
			
		||||
#define RESET_MODE 2
 | 
			
		||||
| 
						 | 
				
			
			@ -531,7 +535,14 @@ class HamShield {
 | 
			
		|||
        bool parityCalc(int code);
 | 
			
		||||
       // void AFSKOut(char buffer[80]); 
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
       // AFSK routines
 | 
			
		||||
       bool AFSKStart();
 | 
			
		||||
       bool AFSKEnabled() { return afsk.enabled(); }
 | 
			
		||||
       bool AFSKStop();
 | 
			
		||||
       bool AFSKOut(const char *);
 | 
			
		||||
       
 | 
			
		||||
       class AFSK afsk;
 | 
			
		||||
       
 | 
			
		||||
    private:
 | 
			
		||||
        uint8_t devAddr;
 | 
			
		||||
        uint16_t radio_i2c_buf[4];
 | 
			
		||||
| 
						 | 
				
			
			@ -542,9 +553,10 @@ class HamShield {
 | 
			
		|||
        uint32_t MURS[];
 | 
			
		||||
        uint32_t WX[];
 | 
			
		||||
        
 | 
			
		||||
    public:
 | 
			
		||||
        // public singleton for ISRs to reference
 | 
			
		||||
      public:
 | 
			
		||||
        static HamShield *sHamShield; // HamShield singleton, used for ISRs mostly
 | 
			
		||||
         
 | 
			
		||||
        
 | 
			
		||||
//          int8_t A1846S::readWord(uint8_t devAddr, uint8_t regAddr, uint16_t *data, uint16_t timeout);
 | 
			
		||||
//          int8_t A1846S::readBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t *data, uint16_t timeout);
 | 
			
		||||
//          int8_t A1846S::readBit(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t *data, uint16_t timeout);
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
| 
						 | 
				
			
			@ -0,0 +1,89 @@
 | 
			
		|||
#ifndef SimpleFIFO_h
 | 
			
		||||
#define SimpleFIFO_h
 | 
			
		||||
/*
 | 
			
		||||
||
 | 
			
		||||
|| @file 		SimpleFIFO.h
 | 
			
		||||
|| @version 	1.2
 | 
			
		||||
|| @author 	Alexander Brevig
 | 
			
		||||
|| @contact 	alexanderbrevig@gmail.com
 | 
			
		||||
||
 | 
			
		||||
|| @description
 | 
			
		||||
|| | A simple FIFO class, mostly for primitive types but can be used with classes if assignment to int is allowed
 | 
			
		||||
|| | This FIFO is not dynamic, so be sure to choose an appropriate size for it
 | 
			
		||||
|| #
 | 
			
		||||
||
 | 
			
		||||
|| @license
 | 
			
		||||
|| | Copyright (c) 2010 Alexander Brevig
 | 
			
		||||
|| | This library is free software; you can redistribute it and/or
 | 
			
		||||
|| | modify it under the terms of the GNU Lesser General Public
 | 
			
		||||
|| | License as published by the Free Software Foundation; version
 | 
			
		||||
|| | 2.1 of the License.
 | 
			
		||||
|| |
 | 
			
		||||
|| | This library is distributed in the hope that it will be useful,
 | 
			
		||||
|| | but WITHOUT ANY WARRANTY; without even the implied warranty of
 | 
			
		||||
|| | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 | 
			
		||||
|| | Lesser General Public License for more details.
 | 
			
		||||
|| |
 | 
			
		||||
|| | You should have received a copy of the GNU Lesser General Public
 | 
			
		||||
|| | License along with this library; if not, write to the Free Software
 | 
			
		||||
|| | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 | 
			
		||||
|| #
 | 
			
		||||
||
 | 
			
		||||
*/
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
class SimpleFIFO {
 | 
			
		||||
public:
 | 
			
		||||
	const int size;				//speculative feature, in case it's needed
 | 
			
		||||
 | 
			
		||||
	SimpleFIFO();
 | 
			
		||||
 | 
			
		||||
	T dequeue();				//get next element
 | 
			
		||||
	bool enqueue( T element );	//add an element
 | 
			
		||||
	T peek() const;				//get the next element without releasing it from the FIFO
 | 
			
		||||
	void flush();				//[1.1] reset to default state 
 | 
			
		||||
 | 
			
		||||
	//how many elements are currently in the FIFO?
 | 
			
		||||
	unsigned char count() { return numberOfElements; }
 | 
			
		||||
 | 
			
		||||
private:
 | 
			
		||||
#ifndef SimpleFIFO_NONVOLATILE
 | 
			
		||||
	volatile unsigned char numberOfElements;
 | 
			
		||||
	volatile unsigned char nextIn;
 | 
			
		||||
	volatile unsigned char nextOut;
 | 
			
		||||
	volatile T raw[rawSize];
 | 
			
		||||
#else
 | 
			
		||||
	unsigned char numberOfElements;
 | 
			
		||||
	unsigned char nextIn;
 | 
			
		||||
	unsigned char nextOut;
 | 
			
		||||
	T raw[rawSize];
 | 
			
		||||
#endif
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
SimpleFIFO<T,rawSize>::SimpleFIFO() : size(rawSize) {
 | 
			
		||||
	flush();
 | 
			
		||||
}
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
bool SimpleFIFO<T,rawSize>::enqueue( T element ) {
 | 
			
		||||
	if ( count() >= rawSize ) { return false; }
 | 
			
		||||
	numberOfElements++;
 | 
			
		||||
	nextIn %= size;
 | 
			
		||||
	raw[nextIn] = element;
 | 
			
		||||
	nextIn++; //advance to next index
 | 
			
		||||
	return true;
 | 
			
		||||
}
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
T SimpleFIFO<T,rawSize>::dequeue() {
 | 
			
		||||
	numberOfElements--;
 | 
			
		||||
	nextOut %= size;
 | 
			
		||||
	return raw[ nextOut++];
 | 
			
		||||
}
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
T SimpleFIFO<T,rawSize>::peek() const {
 | 
			
		||||
	return raw[ nextOut % size];
 | 
			
		||||
}
 | 
			
		||||
template<typename T, int rawSize>
 | 
			
		||||
void SimpleFIFO<T,rawSize>::flush() {
 | 
			
		||||
	nextIn = nextOut = numberOfElements = 0;
 | 
			
		||||
}
 | 
			
		||||
#endif
 | 
			
		||||
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		Reference in New Issue