From 1e065ba17f70cb5f0422b606587d44df9197aa76 Mon Sep 17 00:00:00 2001 From: Jonathan Naylor Date: Sun, 14 Mar 2021 17:53:28 +0000 Subject: [PATCH] Fix and simplify the M17 receiver. --- M17RX.cpp | 141 +++++++++++++++++------------------------------------- M17RX.h | 4 +- Version.h | 2 +- 3 files changed, 46 insertions(+), 101 deletions(-) diff --git a/M17RX.cpp b/M17RX.cpp index f3a0dd2..bf4f56b 100644 --- a/M17RX.cpp +++ b/M17RX.cpp @@ -104,13 +104,9 @@ void CM17RX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length) switch (m_state) { case M17RXS_LINK_SETUP: - processLinkSetup(sample); - break; case M17RXS_STREAM: - processStream(sample); - break; case M17RXS_PACKET: - processPacket(sample); + processData(sample); break; default: processNone(sample); @@ -164,50 +160,34 @@ void CM17RX::processNone(q15_t sample) if (m_maxSyncPtr >= M17_FRAME_LENGTH_SAMPLES) m_maxSyncPtr -= M17_FRAME_LENGTH_SAMPLES; - m_state = m_nextState; - m_countdown = 0U; + m_state = m_nextState; + m_countdown = 0U; + m_nextState = M17RXS_NONE; } } -void CM17RX::processLinkSetup(q15_t sample) -{ - if (m_dataPtr == m_endPtr) { - m_minSyncPtr = m_syncPtr + M17_FRAME_LENGTH_SAMPLES - 1U; - if (m_minSyncPtr >= M17_FRAME_LENGTH_SAMPLES) - m_minSyncPtr -= M17_FRAME_LENGTH_SAMPLES; - - m_maxSyncPtr = m_syncPtr + 1U; - if (m_maxSyncPtr >= M17_FRAME_LENGTH_SAMPLES) - m_maxSyncPtr -= M17_FRAME_LENGTH_SAMPLES; - - calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS); - - DEBUG4("M17RX: link setup sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); - - uint8_t frame[M17_FRAME_LENGTH_BYTES + 3U]; - samplesToBits(m_startPtr, M17_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); - - m_lostCount--; - frame[0U] = 0x01U; - writeRSSIHeader(frame); - - m_state = M17RXS_NONE; - m_endPtr = NOENDPTR; - m_averagePtr = NOAVEPTR; - m_countdown = 0U; - m_nextState = M17RXS_NONE; - m_maxCorr = 0; - } -} - -void CM17RX::processStream(q15_t sample) +void CM17RX::processData(q15_t sample) { if (m_minSyncPtr < m_maxSyncPtr) { - if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr) - correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr) { + bool ret1 = correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + + if (ret1) m_nextState = M17RXS_LINK_SETUP; + if (ret2) m_nextState = M17RXS_STREAM; + if (ret3) m_nextState = M17RXS_PACKET; + } } else { - if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr) - correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr) { + bool ret1 = correlateSync(M17_LINK_SETUP_SYNC_SYMBOLS, M17_LINK_SETUP_SYNC_SYMBOLS_VALUES, M17_LINK_SETUP_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS, M17_STREAM_SYNC_SYMBOLS_VALUES, M17_STREAM_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); + + if (ret1) m_nextState = M17RXS_LINK_SETUP; + if (ret2) m_nextState = M17RXS_STREAM; + if (ret3) m_nextState = M17RXS_PACKET; + } } if (m_dataPtr == m_endPtr) { @@ -224,7 +204,21 @@ void CM17RX::processStream(q15_t sample) calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS); - DEBUG4("M17RX: stream sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); + M17RX_STATE state = m_nextState; + if (state == M17RXS_NONE) + state = m_state; + + switch (state) { + case M17RXS_LINK_SETUP: + DEBUG4("M17RX: link setup sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); + break; + case M17RXS_STREAM: + DEBUG4("M17RX: stream sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); + break; + case M17RXS_PACKET: + DEBUG4("M17RX: packet sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); + break; + } uint8_t frame[M17_FRAME_LENGTH_BYTES + 3U]; samplesToBits(m_startPtr, M17_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); @@ -232,7 +226,7 @@ void CM17RX::processStream(q15_t sample) // We've not seen a stream sync for too long, signal RXLOST and change to RX_NONE m_lostCount--; if (m_lostCount == 0U) { - DEBUG1("M17RX: stream sync timed out, lost lock"); + DEBUG1("M17RX: sync timed out, lost lock"); io.setDecode(false); io.setADCDetection(false); @@ -248,62 +242,15 @@ void CM17RX::processStream(q15_t sample) } else { frame[0U] = 0x00U; frame[0U] |= m_lostCount == (MAX_SYNC_FRAMES - 1U) ? 0x01U : 0x00U; + writeRSSIData(frame); + m_maxCorr = 0; - } - } -} -void CM17RX::processPacket(q15_t sample) -{ - if (m_minSyncPtr < m_maxSyncPtr) { - if (m_dataPtr >= m_minSyncPtr && m_dataPtr <= m_maxSyncPtr) - correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); - } else { - if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr) - correlateSync(M17_PACKET_SYNC_SYMBOLS, M17_PACKET_SYNC_SYMBOLS_VALUES, M17_PACKET_SYNC_BYTES, MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS); - } + if (m_nextState != M17RXS_NONE) + m_state = m_nextState; - if (m_dataPtr == m_endPtr) { - // Only update the centre and threshold if they are from a good sync - if (m_lostCount == MAX_SYNC_FRAMES) { - m_minSyncPtr = m_syncPtr + M17_FRAME_LENGTH_SAMPLES - 1U; - if (m_minSyncPtr >= M17_FRAME_LENGTH_SAMPLES) - m_minSyncPtr -= M17_FRAME_LENGTH_SAMPLES; - - m_maxSyncPtr = m_syncPtr + 1U; - if (m_maxSyncPtr >= M17_FRAME_LENGTH_SAMPLES) - m_maxSyncPtr -= M17_FRAME_LENGTH_SAMPLES; - } - - calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS); - - DEBUG4("M17RX: packet sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); - - uint8_t frame[M17_FRAME_LENGTH_BYTES + 3U]; - samplesToBits(m_startPtr, M17_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); - - // We've not seen a packet sync for too long, signal RXLOST and change to RX_NONE - m_lostCount--; - if (m_lostCount == 0U) { - DEBUG1("M17RX: packet sync timed out, lost lock"); - - io.setDecode(false); - io.setADCDetection(false); - - serial.writeM17Lost(); - - m_state = M17RXS_NONE; - m_endPtr = NOENDPTR; - m_averagePtr = NOAVEPTR; - m_countdown = 0U; - m_nextState = M17RXS_NONE; - m_maxCorr = 0; - } else { - frame[0U] = 0x02U; - frame[0U] |= m_lostCount == (MAX_SYNC_FRAMES - 1U) ? 0x01U : 0x00U; - writeRSSIData(frame); - m_maxCorr = 0; + m_nextState = M17RXS_NONE; } } } diff --git a/M17RX.h b/M17RX.h index e620386..c7637ea 100644 --- a/M17RX.h +++ b/M17RX.h @@ -64,9 +64,7 @@ private: uint16_t m_rssiCount; void processNone(q15_t sample); - void processLinkSetup(q15_t sample); - void processStream(q15_t sample); - void processPacket(q15_t sample); + void processData(q15_t sample); bool correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes, uint8_t maxSymbolErrs, uint8_t maxBitErrs); void calculateLevels(uint16_t start, uint16_t count); void samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset, q15_t centre, q15_t threshold); diff --git a/Version.h b/Version.h index 1f24c03..31dea88 100644 --- a/Version.h +++ b/Version.h @@ -19,7 +19,7 @@ #if !defined(VERSION_H) #define VERSION_H -#define VERSION "20210307" +#define VERSION "20210314" #endif