mirror of https://github.com/g4klx/MMDVM.git
Clean up the M17 synchronisation logic.
This commit is contained in:
parent
bada4d9285
commit
7e919b12f7
56
M17RX.cpp
56
M17RX.cpp
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@ -26,10 +26,11 @@
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const q15_t SCALING_FACTOR = 18750; // Q15(0.55)
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const q15_t SCALING_FACTOR = 18750; // Q15(0.55)
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const uint8_t MAX_SYNC_BIT_START_ERRS = 1U;
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const uint8_t MAX_SYNC_BIT_START_ERRS = 0U;
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const uint8_t MAX_SYNC_BIT_RUN_ERRS = 3U;
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const uint8_t MAX_SYNC_BIT_RUN_ERRS = 2U;
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const uint8_t MAX_SYNC_SYMBOLS_ERRS = 2U;
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const uint8_t MAX_SYNC_SYMBOL_START_ERRS = 0U;
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const uint8_t MAX_SYNC_SYMBOL_RUN_ERRS = 1U;
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const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
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const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
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@ -102,8 +103,8 @@ void CM17RX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
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m_buffer[m_dataPtr] = sample;
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m_buffer[m_dataPtr] = sample;
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switch (m_state) {
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switch (m_state) {
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case M17RXS_HEADER:
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case M17RXS_LINK_SETUP:
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processHeader(sample);
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processLinkSetup(sample);
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break;
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break;
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case M17RXS_STREAM:
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case M17RXS_STREAM:
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processStream(sample);
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processStream(sample);
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@ -128,9 +129,9 @@ void CM17RX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
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void CM17RX::processNone(q15_t sample)
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void CM17RX::processNone(q15_t sample)
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{
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{
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bool ret1 = correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES);
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bool ret1 = correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES, MAX_SYNC_SYMBOL_START_ERRS, MAX_SYNC_BIT_START_ERRS);
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bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES);
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bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_START_ERRS, MAX_SYNC_BIT_START_ERRS);
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bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES);
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bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_START_ERRS, MAX_SYNC_BIT_START_ERRS);
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if (ret1 || ret2 || ret3) {
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if (ret1 || ret2 || ret3) {
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// On the first sync, start the countdown to the state change
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// On the first sync, start the countdown to the state change
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@ -145,7 +146,7 @@ void CM17RX::processNone(q15_t sample)
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m_countdown = 5U;
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m_countdown = 5U;
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if (ret1) m_nextState = M17RXS_HEADER;
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if (ret1) m_nextState = M17RXS_LINK_SETUP;
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if (ret2) m_nextState = M17RXS_STREAM;
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if (ret2) m_nextState = M17RXS_STREAM;
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if (ret3) m_nextState = M17RXS_PACKET;
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if (ret3) m_nextState = M17RXS_PACKET;
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}
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}
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@ -168,16 +169,8 @@ void CM17RX::processNone(q15_t sample)
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}
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}
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}
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}
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void CM17RX::processHeader(q15_t sample)
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void CM17RX::processLinkSetup(q15_t sample)
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{
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{
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if (m_minSyncPtr < m_maxSyncPtr) {
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if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES);
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} else {
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES);
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}
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if (m_dataPtr == m_endPtr) {
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if (m_dataPtr == m_endPtr) {
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m_minSyncPtr = m_syncPtr + M17_FRAME_LENGTH_SAMPLES - 1U;
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m_minSyncPtr = m_syncPtr + M17_FRAME_LENGTH_SAMPLES - 1U;
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if (m_minSyncPtr >= M17_FRAME_LENGTH_SAMPLES)
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if (m_minSyncPtr >= M17_FRAME_LENGTH_SAMPLES)
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@ -189,7 +182,7 @@ void CM17RX::processHeader(q15_t sample)
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calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS);
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calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS);
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DEBUG4("M17RX: header sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal);
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DEBUG4("M17RX: link setup sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal);
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uint8_t frame[M17_FRAME_LENGTH_BYTES + 3U];
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uint8_t frame[M17_FRAME_LENGTH_BYTES + 3U];
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samplesToBits(m_startPtr, M17_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal);
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samplesToBits(m_startPtr, M17_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal);
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@ -197,7 +190,12 @@ void CM17RX::processHeader(q15_t sample)
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m_lostCount--;
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m_lostCount--;
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frame[0U] = 0x01U;
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frame[0U] = 0x01U;
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writeRSSIHeader(frame);
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writeRSSIHeader(frame);
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m_state = M17RXS_NONE;
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m_state = M17RXS_NONE;
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m_endPtr = NOENDPTR;
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m_averagePtr = NOAVEPTR;
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m_countdown = 0U;
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m_nextState = M17RXS_NONE;
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m_maxCorr = 0;
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m_maxCorr = 0;
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}
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}
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}
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}
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@ -206,10 +204,10 @@ void CM17RX::processStream(q15_t sample)
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{
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{
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if (m_minSyncPtr < m_maxSyncPtr) {
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if (m_minSyncPtr < m_maxSyncPtr) {
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if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr)
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if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES);
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correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
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} else {
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} else {
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES);
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correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
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}
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}
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if (m_dataPtr == m_endPtr) {
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if (m_dataPtr == m_endPtr) {
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@ -260,10 +258,10 @@ void CM17RX::processPacket(q15_t sample)
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{
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{
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if (m_minSyncPtr < m_maxSyncPtr) {
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if (m_minSyncPtr < m_maxSyncPtr) {
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if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr)
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if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES);
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correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
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} else {
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} else {
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES);
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correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
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}
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}
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if (m_dataPtr == m_endPtr) {
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if (m_dataPtr == m_endPtr) {
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@ -310,9 +308,9 @@ void CM17RX::processPacket(q15_t sample)
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}
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}
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}
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}
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bool CM17RX::correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes)
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bool CM17RX::correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes, uint8_t maxSymbolErrs, uint8_t maxBitErrs)
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{
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{
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if (countBits8(m_bitBuffer[m_bitPtr] ^ syncSymbols) <= MAX_SYNC_SYMBOLS_ERRS) {
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if (countBits8(m_bitBuffer[m_bitPtr] ^ syncSymbols) <= maxSymbolErrs) {
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uint16_t ptr = m_dataPtr + M17_FRAME_LENGTH_SAMPLES - M17_SYNC_LENGTH_SAMPLES + M17_RADIO_SYMBOL_LENGTH;
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uint16_t ptr = m_dataPtr + M17_FRAME_LENGTH_SAMPLES - M17_SYNC_LENGTH_SAMPLES + M17_RADIO_SYMBOL_LENGTH;
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if (ptr >= M17_FRAME_LENGTH_SAMPLES)
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if (ptr >= M17_FRAME_LENGTH_SAMPLES)
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ptr -= M17_FRAME_LENGTH_SAMPLES;
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ptr -= M17_FRAME_LENGTH_SAMPLES;
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@ -364,17 +362,11 @@ bool CM17RX::correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues,
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uint8_t sync[M17_SYNC_BYTES_LENGTH];
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uint8_t sync[M17_SYNC_BYTES_LENGTH];
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samplesToBits(startPtr, M17_SYNC_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal);
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samplesToBits(startPtr, M17_SYNC_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal);
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uint8_t maxErrs;
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if (m_state == M17RXS_NONE)
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maxErrs = MAX_SYNC_BIT_START_ERRS;
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else
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maxErrs = MAX_SYNC_BIT_RUN_ERRS;
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uint8_t errs = 0U;
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uint8_t errs = 0U;
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for (uint8_t i = 0U; i < M17_SYNC_BYTES_LENGTH; i++)
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for (uint8_t i = 0U; i < M17_SYNC_BYTES_LENGTH; i++)
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errs += countBits8(sync[i] ^ syncBytes[i]);
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errs += countBits8(sync[i] ^ syncBytes[i]);
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if (errs <= maxErrs) {
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if (errs <= maxBitErrs) {
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m_maxCorr = corr;
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m_maxCorr = corr;
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m_lostCount = MAX_SYNC_FRAMES;
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m_lostCount = MAX_SYNC_FRAMES;
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m_syncPtr = m_dataPtr;
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m_syncPtr = m_dataPtr;
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6
M17RX.h
6
M17RX.h
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@ -27,7 +27,7 @@
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enum M17RX_STATE {
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enum M17RX_STATE {
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M17RXS_NONE,
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M17RXS_NONE,
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M17RXS_HEADER,
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M17RXS_LINK_SETUP,
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M17RXS_STREAM,
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M17RXS_STREAM,
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M17RXS_PACKET
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M17RXS_PACKET
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};
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};
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@ -64,10 +64,10 @@ private:
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uint16_t m_rssiCount;
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uint16_t m_rssiCount;
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void processNone(q15_t sample);
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void processNone(q15_t sample);
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void processHeader(q15_t sample);
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void processLinkSetup(q15_t sample);
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void processStream(q15_t sample);
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void processStream(q15_t sample);
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void processPacket(q15_t sample);
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void processPacket(q15_t sample);
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bool correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes);
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bool correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes, uint8_t maxSymbolErrs, uint8_t maxBitErrs);
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void calculateLevels(uint16_t start, uint16_t count);
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void calculateLevels(uint16_t start, uint16_t count);
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void samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset, q15_t centre, q15_t threshold);
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void samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset, q15_t centre, q15_t threshold);
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void writeRSSIHeader(uint8_t* data);
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void writeRSSIHeader(uint8_t* data);
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