mirror of
https://github.com/g4klx/MMDVM.git
synced 2026-08-21 14:36:21 +02:00
Use the D-Star correlator receiver.
This commit is contained in:
Jonathan Naylor
+238
-137
@@ -1,5 +1,5 @@
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/*
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* Copyright (C) 2009-2017 by Jonathan Naylor G4KLX
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* Copyright (C) 2009-2017,2020 by Jonathan Naylor G4KLX
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* Copyright (C) 2017 by Andy Uribe CA6JAU
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*
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* This program is free software; you can redistribute it and/or modify
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@@ -25,18 +25,12 @@
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#include "DStarRX.h"
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#include "Utils.h"
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const unsigned int BUFFER_LENGTH = 200U;
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const uint32_t PLLMAX = 0x10000U;
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const uint32_t PLLINC = PLLMAX / DSTAR_RADIO_BIT_LENGTH;
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const uint32_t INC = PLLINC / 32U;
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const unsigned int MAX_SYNC_BITS = 100U * DSTAR_DATA_LENGTH_BITS;
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const unsigned int MAX_FRAMES = 150U;
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// D-Star bit order version of 0x55 0x55 0x6E 0x0A
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const uint32_t FRAME_SYNC_DATA = 0x00557650U;
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const uint32_t FRAME_SYNC_MASK = 0x00FFFFFFU;
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const uint8_t FRAME_SYNC_ERRS = 2U;
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const uint8_t FRAME_SYNC_ERRS = 1U;
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// D-Star bit order version of 0x55 0x2D 0x16
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const uint32_t DATA_SYNC_DATA = 0x00AAB468U;
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@@ -240,14 +234,24 @@ const uint16_t CCITT_TABLE[] = {
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0xf78fU, 0xe606U, 0xd49dU, 0xc514U, 0xb1abU, 0xa022U, 0x92b9U, 0x8330U,
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0x7bc7U, 0x6a4eU, 0x58d5U, 0x495cU, 0x3de3U, 0x2c6aU, 0x1ef1U, 0x0f78U};
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const uint16_t NOENDPTR = 9999U;
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CDStarRX::CDStarRX() :
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m_pll(0U),
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m_prev(false),
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m_rxState(DSRXS_NONE),
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m_patternBuffer(0x00U),
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m_rxBuffer(),
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m_rxBufferBits(0U),
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m_dataBits(0U),
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m_bitBuffer(),
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m_headerBuffer(),
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m_dataBuffer(),
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m_bitPtr(0U),
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m_headerPtr(0U),
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m_dataPtr(0U),
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m_startPtr(NOENDPTR),
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m_syncPtr(NOENDPTR),
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m_minSyncPtr(NOENDPTR),
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m_maxSyncPtr(NOENDPTR),
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m_maxFrameCorr(0),
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m_maxDataCorr(0),
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m_frameCount(0U),
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m_countdown(0U),
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m_mar(0U),
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m_pathMetric(),
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m_pathMemory0(),
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@@ -262,14 +266,20 @@ m_rssiCount(0U)
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void CDStarRX::reset()
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{
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m_pll = 0U;
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m_prev = false;
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m_rxState = DSRXS_NONE;
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m_patternBuffer = 0x00U;
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m_rxBufferBits = 0U;
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m_dataBits = 0U;
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m_rssiAccum = 0U;
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m_rssiCount = 0U;
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m_rxState = DSRXS_NONE;
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m_headerPtr = 0U;
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m_dataPtr = 0U;
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m_bitPtr = 0U;
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m_maxFrameCorr = 0;
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m_maxDataCorr = 0;
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m_startPtr = NOENDPTR;
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m_syncPtr = NOENDPTR;
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m_minSyncPtr = NOENDPTR;
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m_maxSyncPtr = NOENDPTR;
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m_frameCount = 0U;
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m_countdown = 0U;
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m_rssiAccum = 0U;
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m_rssiCount = 0U;
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}
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void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t length)
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@@ -278,125 +288,117 @@ void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t lengt
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m_rssiAccum += rssi[i];
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m_rssiCount++;
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bool bit = samples[i] < 0;
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q15_t sample = samples[i];
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if (bit != m_prev) {
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if (m_pll < (PLLMAX / 2U))
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m_pll += INC;
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else
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m_pll -= INC;
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m_bitBuffer[m_bitPtr] <<= 1;
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if (sample < 0)
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m_bitBuffer[m_bitPtr] |= 0x01U;
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m_dataBuffer[m_dataPtr] = sample;
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switch (m_rxState) {
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case DSRXS_HEADER:
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processHeader(sample);
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break;
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case DSRXS_DATA:
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processData();
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break;
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default:
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processNone(sample);
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break;
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}
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m_prev = bit;
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m_dataPtr++;
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if (m_dataPtr >= DSTAR_DATA_LENGTH_SAMPLES)
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m_dataPtr = 0U;
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m_pll += PLLINC;
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if (m_pll >= PLLMAX) {
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m_pll -= PLLMAX;
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switch (m_rxState) {
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case DSRXS_NONE:
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processNone(bit);
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break;
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case DSRXS_HEADER:
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processHeader(bit);
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break;
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case DSRXS_DATA:
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processData(bit);
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break;
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default:
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break;
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}
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}
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m_bitPtr++;
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if (m_bitPtr >= DSTAR_RADIO_SYMBOL_LENGTH)
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m_bitPtr = 0U;
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}
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}
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void CDStarRX::processNone(bool bit)
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void CDStarRX::processNone(q15_t sample)
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{
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m_patternBuffer <<= 1;
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if (bit)
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m_patternBuffer |= 0x01U;
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// Fuzzy matching of the frame sync sequence
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if (countBits32((m_patternBuffer & FRAME_SYNC_MASK) ^ FRAME_SYNC_DATA) <= FRAME_SYNC_ERRS) {
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DEBUG1("DStarRX: found frame sync in None");
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bool ret = correlateFrameSync();
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if (ret) {
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m_countdown = 5U;
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::memset(m_rxBuffer, 0x00U, DSTAR_FEC_SECTION_LENGTH_BYTES);
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m_rxBufferBits = 0U;
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m_headerBuffer[m_headerPtr] = sample;
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m_headerPtr++;
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m_rssiAccum = 0U;
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m_rssiCount = 0U;
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m_rxState = DSRXS_HEADER;
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return;
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}
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// Exact matching of the data sync bit sequence
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if (countBits32((m_patternBuffer & DATA_SYNC_MASK) ^ DATA_SYNC_DATA) == 0U) {
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// Fuzzy matching of the data sync bit sequence
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ret = correlateDataSync();
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if (ret) {
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DEBUG1("DStarRX: found data sync in None");
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io.setDecode(true);
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io.setADCDetection(true);
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// Suppress RSSI on the dummy sync message
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m_rssiAccum = 0U;
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m_rssiCount = 0U;
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::memcpy(m_rxBuffer, DSTAR_DATA_SYNC_BYTES, DSTAR_DATA_LENGTH_BYTES);
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writeRSSIData(m_rxBuffer);
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::memset(m_rxBuffer, 0x00U, DSTAR_DATA_LENGTH_BYTES + 2U);
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m_rxBufferBits = 0U;
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m_dataBits = MAX_SYNC_BITS;
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m_rxState = DSRXS_DATA;
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return;
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m_rxState = DSRXS_DATA;
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}
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}
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void CDStarRX::processHeader(bool bit)
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void CDStarRX::processHeader(q15_t sample)
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{
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m_patternBuffer <<= 1;
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if (bit)
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m_patternBuffer |= 0x01U;
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if (m_countdown > 0U) {
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correlateFrameSync();
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m_countdown--;
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}
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WRITE_BIT2(m_rxBuffer, m_rxBufferBits, bit);
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m_rxBufferBits++;
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m_headerBuffer[m_headerPtr] = sample;
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m_headerPtr++;
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// A full FEC header
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if (m_rxBufferBits == DSTAR_FEC_SECTION_LENGTH_BITS) {
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// Process the scrambling, interleaving and FEC, then return if the chcksum was correct
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unsigned char header[DSTAR_HEADER_LENGTH_BYTES];
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bool ok = rxHeader(m_rxBuffer, header);
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if (ok) {
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if (m_headerPtr == (DSTAR_FEC_SECTION_LENGTH_SAMPLES + DSTAR_RADIO_SYMBOL_LENGTH)) {
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uint8_t buffer[DSTAR_FEC_SECTION_LENGTH_BYTES];
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samplesToBits(m_headerBuffer, DSTAR_RADIO_SYMBOL_LENGTH, DSTAR_FEC_SECTION_LENGTH_SYMBOLS, buffer, DSTAR_FEC_SECTION_LENGTH_SAMPLES);
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// Process the scrambling, interleaving and FEC, then return true if the chcksum was correct
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uint8_t header[DSTAR_HEADER_LENGTH_BYTES];
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bool ok = rxHeader(buffer, header);
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if (!ok) {
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// The checksum failed, return to looking for syncs
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m_rxState = DSRXS_NONE;
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m_maxFrameCorr = 0;
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m_maxDataCorr = 0;
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} else {
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io.setDecode(true);
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io.setADCDetection(true);
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writeRSSIHeader(header);
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::memset(m_rxBuffer, 0x00U, DSTAR_DATA_LENGTH_BYTES + 2U);
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m_rxBufferBits = 0U;
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m_rxState = DSRXS_DATA;
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m_dataBits = MAX_SYNC_BITS;
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} else {
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// The checksum failed, return to looking for syncs
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m_rxState = DSRXS_NONE;
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}
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}
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// Ready to start the first data section
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if (m_headerPtr == (DSTAR_FEC_SECTION_LENGTH_SAMPLES + 2U * DSTAR_RADIO_SYMBOL_LENGTH)) {
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m_frameCount = 0U;
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m_dataPtr = 0U;
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m_startPtr = 476U;
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m_syncPtr = 471U;
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m_maxSyncPtr = 472U;
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m_minSyncPtr = 470U;
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DEBUG5("DStarRX: calc start/sync/max/min", m_startPtr, m_syncPtr, m_maxSyncPtr, m_minSyncPtr);
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m_rxState = DSRXS_DATA;
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}
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}
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void CDStarRX::processData(bool bit)
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void CDStarRX::processData()
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{
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m_patternBuffer <<= 1;
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if (bit)
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m_patternBuffer |= 0x01U;
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WRITE_BIT2(m_rxBuffer, m_rxBufferBits, bit);
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m_rxBufferBits++;
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// Fuzzy matching of the end frame sequences
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if (countBits32((m_patternBuffer & END_SYNC_MASK) ^ END_SYNC_DATA) <= END_SYNC_ERRS) {
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if (countBits32((m_bitBuffer[m_bitPtr] & DSTAR_END_SYNC_MASK) ^ DSTAR_END_SYNC_DATA) <= END_SYNC_ERRS) {
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DEBUG1("DStarRX: Found end sync in Data");
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io.setDecode(false);
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@@ -404,35 +406,24 @@ void CDStarRX::processData(bool bit)
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serial.writeDStarEOT();
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m_maxFrameCorr = 0;
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m_maxDataCorr = 0;
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m_rxState = DSRXS_NONE;
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return;
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}
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// Fuzzy matching of the data sync bit sequence
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bool syncSeen = false;
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if (m_rxBufferBits >= (DSTAR_DATA_LENGTH_BITS - 3U)) {
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if (countBits32((m_patternBuffer & DATA_SYNC_MASK) ^ DATA_SYNC_DATA) <= DATA_SYNC_ERRS) {
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m_rxBufferBits = DSTAR_DATA_LENGTH_BITS;
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m_dataBits = MAX_SYNC_BITS;
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syncSeen = true;
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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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correlateDataSync();
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} else {
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if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr)
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correlateDataSync();
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}
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// Check to see if the sync is arriving late
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if (m_rxBufferBits == DSTAR_DATA_LENGTH_BITS && !syncSeen) {
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for (uint8_t i = 1U; i <= 3U; i++) {
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uint32_t syncMask = DATA_SYNC_MASK >> i;
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uint32_t syncData = DATA_SYNC_DATA >> i;
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if (countBits32((m_patternBuffer & syncMask) ^ syncData) <= DATA_SYNC_ERRS) {
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m_rxBufferBits -= i;
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break;
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}
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}
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}
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m_dataBits--;
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if (m_dataBits == 0U) {
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// We've not seen a data sync for too long, signal RXLOST and change to RX_NONE
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if (m_frameCount >= MAX_FRAMES) {
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DEBUG1("DStarRX: data sync timed out, lost lock");
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io.setDecode(false);
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@@ -440,24 +431,35 @@ void CDStarRX::processData(bool bit)
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serial.writeDStarLost();
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m_maxFrameCorr = 0;
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m_maxDataCorr = 0;
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m_rxState = DSRXS_NONE;
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return;
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}
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// Send a data frame to the host if the required number of bits have been received, or if a data sync has been seen
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if (m_rxBufferBits == DSTAR_DATA_LENGTH_BITS) {
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if (syncSeen) {
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m_rxBuffer[9U] = DSTAR_DATA_SYNC_BYTES[9U];
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m_rxBuffer[10U] = DSTAR_DATA_SYNC_BYTES[10U];
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m_rxBuffer[11U] = DSTAR_DATA_SYNC_BYTES[11U];
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writeRSSIData(m_rxBuffer);
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} else {
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serial.writeDStarData(m_rxBuffer, DSTAR_DATA_LENGTH_BYTES);
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}
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// Send a data frame to the host if the required number of bits have been received
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if (m_dataPtr == m_maxSyncPtr) {
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uint8_t buffer[DSTAR_DATA_LENGTH_BYTES + 2U];
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samplesToBits(m_dataBuffer, m_startPtr, DSTAR_DATA_LENGTH_SYMBOLS, buffer, DSTAR_DATA_LENGTH_SAMPLES);
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// Start the next frame
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::memset(m_rxBuffer, 0x00U, DSTAR_DATA_LENGTH_BYTES + 2U);
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m_rxBufferBits = 0U;
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if ((m_frameCount % 21U) == 0U) {
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if (m_frameCount == 0U) {
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buffer[9U] = DSTAR_DATA_SYNC_BYTES[9U];
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buffer[10U] = DSTAR_DATA_SYNC_BYTES[10U];
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buffer[11U] = DSTAR_DATA_SYNC_BYTES[11U];
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DEBUG5("DStarRX: found start/sync/max/min", m_startPtr, m_syncPtr, m_maxSyncPtr, m_minSyncPtr);
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}
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writeRSSIData(buffer);
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} else {
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serial.writeDStarData(buffer, DSTAR_DATA_LENGTH_BYTES);
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}
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m_frameCount++;
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m_maxFrameCorr = 0;
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m_maxDataCorr = 0;
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}
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}
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@@ -503,6 +505,105 @@ void CDStarRX::writeRSSIData(unsigned char* data)
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m_rssiCount = 0U;
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}
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bool CDStarRX::correlateFrameSync()
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{
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if (countBits32((m_bitBuffer[m_bitPtr] & DSTAR_FRAME_SYNC_MASK) ^ DSTAR_FRAME_SYNC_DATA) <= FRAME_SYNC_ERRS) {
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uint16_t ptr = m_dataPtr + DSTAR_DATA_LENGTH_SAMPLES - DSTAR_FRAME_SYNC_LENGTH_SAMPLES + DSTAR_RADIO_SYMBOL_LENGTH;
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if (ptr >= DSTAR_DATA_LENGTH_SAMPLES)
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ptr -= DSTAR_DATA_LENGTH_SAMPLES;
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q31_t corr = 0;
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for (uint8_t i = 0U; i < DSTAR_FRAME_SYNC_LENGTH_SYMBOLS; i++) {
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q15_t val = m_dataBuffer[ptr];
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if (DSTAR_FRAME_SYNC_SYMBOLS[i])
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corr -= val;
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else
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corr += val;
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ptr += DSTAR_RADIO_SYMBOL_LENGTH;
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if (ptr >= DSTAR_DATA_LENGTH_SAMPLES)
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ptr -= DSTAR_DATA_LENGTH_SAMPLES;
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}
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if (corr > m_maxFrameCorr) {
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m_maxFrameCorr = corr;
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m_headerPtr = 0U;
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return true;
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}
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}
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return false;
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}
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bool CDStarRX::correlateDataSync()
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{
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uint8_t maxErrs = 0U;
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if (m_rxState == DSRXS_DATA)
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maxErrs = DATA_SYNC_ERRS;
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if (countBits32((m_bitBuffer[m_bitPtr] & DSTAR_DATA_SYNC_MASK) ^ DSTAR_DATA_SYNC_DATA) <= maxErrs) {
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uint16_t ptr = m_dataPtr + DSTAR_DATA_LENGTH_SAMPLES - DSTAR_DATA_SYNC_LENGTH_SAMPLES + DSTAR_RADIO_SYMBOL_LENGTH;
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if (ptr >= DSTAR_DATA_LENGTH_SAMPLES)
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ptr -= DSTAR_DATA_LENGTH_SAMPLES;
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q31_t corr = 0;
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for (uint8_t i = 0U; i < DSTAR_DATA_SYNC_LENGTH_SYMBOLS; i++) {
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q15_t val = m_dataBuffer[ptr];
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if (DSTAR_DATA_SYNC_SYMBOLS[i])
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corr -= val;
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else
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corr += val;
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ptr += DSTAR_RADIO_SYMBOL_LENGTH;
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if (ptr >= DSTAR_DATA_LENGTH_SAMPLES)
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ptr -= DSTAR_DATA_LENGTH_SAMPLES;
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}
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||||
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if (corr > m_maxDataCorr) {
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m_maxDataCorr = corr;
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m_frameCount = 0U;
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||||
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m_syncPtr = m_dataPtr;
|
||||
|
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m_startPtr = m_dataPtr + DSTAR_RADIO_SYMBOL_LENGTH;
|
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if (m_startPtr >= DSTAR_DATA_LENGTH_SAMPLES)
|
||||
m_startPtr -= DSTAR_DATA_LENGTH_SAMPLES;
|
||||
|
||||
m_maxSyncPtr = m_syncPtr + 1U;
|
||||
if (m_maxSyncPtr >= DSTAR_DATA_LENGTH_SAMPLES)
|
||||
m_maxSyncPtr -= DSTAR_DATA_LENGTH_SAMPLES;
|
||||
|
||||
m_minSyncPtr = m_syncPtr + DSTAR_DATA_LENGTH_SAMPLES - 1U;
|
||||
if (m_minSyncPtr >= DSTAR_DATA_LENGTH_SAMPLES)
|
||||
m_minSyncPtr -= DSTAR_DATA_LENGTH_SAMPLES;
|
||||
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
void CDStarRX::samplesToBits(const q15_t* inBuffer, uint16_t start, uint16_t count, uint8_t* outBuffer, uint16_t limit)
|
||||
{
|
||||
for (uint16_t i = 0U; i < count; i++) {
|
||||
q15_t sample = inBuffer[start];
|
||||
|
||||
if (sample < 0)
|
||||
WRITE_BIT2(outBuffer, i, true);
|
||||
else
|
||||
WRITE_BIT2(outBuffer, i, false);
|
||||
|
||||
start += DSTAR_RADIO_SYMBOL_LENGTH;
|
||||
if (start >= limit)
|
||||
start -= limit;
|
||||
}
|
||||
}
|
||||
|
||||
bool CDStarRX::rxHeader(uint8_t* in, uint8_t* out)
|
||||
{
|
||||
int i;
|
||||
|
||||
Reference in New Issue
Block a user