mirror of https://github.com/g4klx/MMDVM.git
150 lines
3.9 KiB
C++
150 lines
3.9 KiB
C++
/*
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* Copyright (C) 2009-2018,2020 by Jonathan Naylor G4KLX
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Config.h"
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#include "Globals.h"
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#include "POCSAGTX.h"
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const uint16_t POCSAG_FRAME_LENGTH_BYTES = 17U * sizeof(uint32_t);
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const uint16_t POCSAG_PREAMBLE_LENGTH_BYTES = 18U * sizeof(uint32_t);
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const uint16_t POCSAG_RADIO_SYMBOL_LENGTH = 20U;
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const q15_t POCSAG_LEVEL1[] = { 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700, 1700};
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const q15_t POCSAG_LEVEL0[] = {-1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700, -1700};
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static q15_t SHAPING_FILTER[] = {5461, 5461, 5461, 5461, 5461, 5461};
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const uint16_t SHAPING_FILTER_LEN = 6U;
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const uint8_t POCSAG_SYNC = 0xAAU;
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CPOCSAGTX::CPOCSAGTX() :
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m_buffer(4000U),
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m_modFilter(),
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m_modState(),
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m_poBuffer(),
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m_poLen(0U),
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m_poPtr(0U),
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m_txDelay(POCSAG_PREAMBLE_LENGTH_BYTES)
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{
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::memset(m_modState, 0x00U, 170U * sizeof(q15_t));
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m_modFilter.numTaps = SHAPING_FILTER_LEN;
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m_modFilter.pState = m_modState;
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m_modFilter.pCoeffs = SHAPING_FILTER;
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}
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void CPOCSAGTX::process()
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{
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if (m_buffer.getData() == 0U && m_poLen == 0U)
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return;
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if (m_poLen == 0U) {
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if (!m_tx) {
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for (uint16_t i = 0U; i < m_txDelay; i++)
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m_poBuffer[m_poLen++] = POCSAG_SYNC;
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} else {
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for (uint8_t i = 0U; i < POCSAG_FRAME_LENGTH_BYTES; i++) {
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uint8_t c = m_buffer.get();
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m_poBuffer[m_poLen++] = c;
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}
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}
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m_poPtr = 0U;
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}
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if (m_poLen > 0U) {
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uint16_t space = io.getSpace();
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while (space > (8U * POCSAG_RADIO_SYMBOL_LENGTH)) {
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uint8_t c = m_poBuffer[m_poPtr++];
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writeByte(c);
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space -= 8U * POCSAG_RADIO_SYMBOL_LENGTH;
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if (m_poPtr >= m_poLen) {
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m_poPtr = 0U;
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m_poLen = 0U;
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return;
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}
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}
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}
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}
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bool CPOCSAGTX::busy()
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{
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if (m_poLen > 0U || m_buffer.getData() > 0U)
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return true;
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else
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return false;
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}
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uint8_t CPOCSAGTX::writeData(const uint8_t* data, uint16_t length)
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{
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if (length != POCSAG_FRAME_LENGTH_BYTES)
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return 4U;
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uint16_t space = m_buffer.getSpace();
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if (space < POCSAG_FRAME_LENGTH_BYTES)
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return 5U;
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for (uint8_t i = 0U; i < POCSAG_FRAME_LENGTH_BYTES; i++)
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m_buffer.put(data[i]);
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return 0U;
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}
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void CPOCSAGTX::writeByte(uint8_t c)
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{
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q15_t inBuffer[POCSAG_RADIO_SYMBOL_LENGTH * 8U];
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q15_t outBuffer[POCSAG_RADIO_SYMBOL_LENGTH * 8U];
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const uint8_t MASK = 0x80U;
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uint8_t n = 0U;
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for (uint8_t i = 0U; i < 8U; i++, c <<= 1, n += POCSAG_RADIO_SYMBOL_LENGTH) {
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switch (c & MASK) {
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case 0x80U:
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::memcpy(inBuffer + n, POCSAG_LEVEL1, POCSAG_RADIO_SYMBOL_LENGTH * sizeof(q15_t));
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break;
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default:
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::memcpy(inBuffer + n, POCSAG_LEVEL0, POCSAG_RADIO_SYMBOL_LENGTH * sizeof(q15_t));
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break;
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}
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}
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::arm_fir_fast_q15(&m_modFilter, inBuffer, outBuffer, POCSAG_RADIO_SYMBOL_LENGTH * 8U);
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io.write(STATE_POCSAG, outBuffer, POCSAG_RADIO_SYMBOL_LENGTH * 8U);
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}
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void CPOCSAGTX::setTXDelay(uint8_t delay)
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{
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m_txDelay = POCSAG_PREAMBLE_LENGTH_BYTES + (delay * 3U) / 2U;
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if (m_txDelay > 150U)
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m_txDelay = 150U;
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}
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uint8_t CPOCSAGTX::getSpace() const
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{
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return m_buffer.getSpace() / POCSAG_FRAME_LENGTH_BYTES;
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}
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