Reorganise the source code.

src/AX25/AX25TX.cpp

@@ -0,0 +1,191 @@
+/*
+ *   Copyright (C) 2020 by Jonathan Naylor G4KLX
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "Config.h"
+
+#if defined(MODE_AX25)
+
+#include "Globals.h"
+#include "AX25TX.h"
+
+#include "AX25Defines.h"
+#include "AX25Frame.h"
+
+
+const uint8_t START_FLAG[] = { AX25_FRAME_START };
+const uint8_t END_FLAG[]   = { AX25_FRAME_END };
+
+const uint8_t BIT_MASK_TABLE1[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
+
+#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE1[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE1[(i)&7])
+#define READ_BIT1(p,i)    (p[(i)>>3] & BIT_MASK_TABLE1[(i)&7])
+
+const uint8_t BIT_MASK_TABLE2[] = { 0x01U, 0x02U, 0x04U, 0x08U, 0x10U, 0x20U, 0x40U, 0x80U };
+
+#define WRITE_BIT2(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE2[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE2[(i)&7])
+#define READ_BIT2(p,i)    (p[(i)>>3] & BIT_MASK_TABLE2[(i)&7])
+
+const uint16_t AUDIO_TABLE_LEN = 120U;
+
+const q15_t AUDIO_TABLE_DATA[] = {
+  0, 214, 428, 641, 851, 1060, 1265, 1468, 1666, 1859, 2048, 2230, 2407, 2577, 2740, 2896, 3043, 3182, 3313, 3434, 3546, 3649,
+  3741, 3823, 3895, 3955, 4006, 4045, 4073, 4089, 4095, 4089, 4073, 4045, 4006, 3955, 3895, 3823, 3741, 3649, 3546, 3434, 3313,
+  3182, 3043, 2896, 2740, 2577, 2407, 2230, 2048, 1859, 1666, 1468, 1265, 1060, 851, 641, 428, 214, 0, -214, -428, -641, -851,
+  -1060, -1265, -1468, -1666, -1859, -2047, -2230, -2407, -2577, -2740, -2896, -3043, -3182, -3313, -3434, -3546, -3649, -3741,
+  -3823, -3895, -3955, -4006, -4045, -4073, -4089, -4095, -4089, -4073, -4045, -4006, -3955, -3895, -3823, -3741, -3649, -3546,
+  -3434, -3313, -3182, -3043, -2896, -2740, -2577, -2407, -2230, -2047, -1859, -1666, -1468, -1265, -1060, -851, -641, -428, -214
+};
+
+CAX25TX::CAX25TX() :
+m_poBuffer(),
+m_poLen(0U),
+m_poPtr(0U),
+m_txDelay(360U),
+m_tablePtr(0U),
+m_nrzi(false)
+{
+}
+
+void CAX25TX::process()
+{
+  if (m_poLen == 0U)
+    return;
+
+  if (!m_duplex) {
+    if (m_poPtr == 0U) {
+      bool tx = ax25RX.canTX();
+      if (!tx)
+        return;
+    }
+  }
+
+  uint16_t space = io.getSpace();
+
+  while (space > AX25_RADIO_SYMBOL_LENGTH) {
+    bool b = READ_BIT1(m_poBuffer, m_poPtr) != 0U;
+    m_poPtr++;
+
+    writeBit(b);
+
+    space -= AX25_RADIO_SYMBOL_LENGTH;
+
+    if (m_poPtr >= m_poLen) {
+      m_poPtr = 0U;
+      m_poLen = 0U;
+      return;
+    }
+  }
+}
+
+uint8_t CAX25TX::writeData(const uint8_t* data, uint16_t length)
+{
+  CAX25Frame frame(data, length);
+  frame.addCRC();
+
+  m_poLen    = 0U;
+  m_poPtr    = 0U;
+  m_nrzi     = false;
+  m_tablePtr = 0U;
+
+  // Add TX delay
+  for (uint16_t i = 0U; i < m_txDelay; i++, m_poLen++) {
+    bool preamble = NRZI(false);
+    WRITE_BIT1(m_poBuffer, m_poLen, preamble);
+  }
+
+  // Add the Start Flag
+  for (uint16_t i = 0U; i < 8U; i++, m_poLen++) {
+    bool b1 = READ_BIT1(START_FLAG, i) != 0U;
+    bool b2 = NRZI(b1);
+    WRITE_BIT1(m_poBuffer, m_poLen, b2);
+  }
+
+  uint8_t ones = 0U;
+  for (uint16_t i = 0U; i < (frame.m_length * 8U); i++) {
+    bool b1 = READ_BIT2(frame.m_data, i) != 0U;
+    bool b2 = NRZI(b1);
+    WRITE_BIT1(m_poBuffer, m_poLen, b2);
+    m_poLen++;
+
+    if (b1) {
+      ones++;
+      if (ones == AX25_MAX_ONES) {
+        // Bit stuffing
+        bool b = NRZI(false);
+        WRITE_BIT1(m_poBuffer, m_poLen, b);
+        m_poLen++;
+        ones = 0U;
+      }
+    } else {
+      ones = 0U;
+    }
+  }
+
+  // Add the End Flag
+  for (uint16_t i = 0U; i < 8U; i++, m_poLen++) {
+    bool b1 = READ_BIT1(END_FLAG, i) != 0U;
+    bool b2 = NRZI(b1);
+    WRITE_BIT1(m_poBuffer, m_poLen, b2);
+  }
+
+  return 0U;
+}
+
+void CAX25TX::writeBit(bool b)
+{
+  q15_t buffer[AX25_RADIO_SYMBOL_LENGTH];
+  for (uint8_t i = 0U; i < AX25_RADIO_SYMBOL_LENGTH; i++) {
+    q15_t value = AUDIO_TABLE_DATA[m_tablePtr];
+
+    if (b) {
+      // De-emphasise the lower frequency by 6dB
+      value >>= 2;
+      m_tablePtr += 6U;
+    } else {
+      m_tablePtr += 11U;
+    }
+
+    buffer[i] = value >> 1;
+
+    if (m_tablePtr >= AUDIO_TABLE_LEN)
+      m_tablePtr -= AUDIO_TABLE_LEN;
+  }
+
+  io.write(STATE_AX25, buffer, AX25_RADIO_SYMBOL_LENGTH);
+}
+
+void CAX25TX::setTXDelay(uint8_t delay)
+{
+  m_txDelay = delay * 12U;
+}
+
+uint8_t CAX25TX::getSpace() const
+{
+  return m_poLen == 0U ? 255U : 0U;
+}
+
+bool CAX25TX::NRZI(bool b)
+{
+    if (!b)
+      m_nrzi = !m_nrzi;
+
+    return m_nrzi;
+}
+
+#endif
+