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Clean up the M17 synchronisation.

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This commit is contained in:
Jonathan Naylor 2021-01-02 12:28:19 +00:00
parent 4f1ed20d77
commit 2f52282c47
3 changed files with 16 additions and 28 deletions
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38
M17RX.cpp
View file

@ -25,7 +25,7 @@
const uint8_t MAX_SYNC_BIT_START_ERRS = 0U; const uint8_t MAX_SYNC_BIT_START_ERRS = 0U;
const uint8_t MAX_SYNC_BIT_RUN_ERRS = 2U; const uint8_t MAX_SYNC_BIT_RUN_ERRS = 2U;
const unsigned int MAX_SYNC_FRAMES = 5U + 1U; const unsigned int MAX_SYNC_FRAMES = 3U + 1U;
const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U}; const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
@ -53,17 +53,17 @@ void CM17RX::reset()
void CM17RX::databit(bool bit) void CM17RX::databit(bool bit)
{ {
switch (m_state) { switch (m_state) {
case M17RXS_NONE: case M17RXS_LINK_SETUP:
processNone(bit); processLinkSetup(bit);
break; break;
case M17RXS_HEADER: case M17RXS_STREAM:
processHeader(bit); processStream(bit);
break; break;
case M17RXS_PACKET: case M17RXS_PACKET:
processPacket(bit); processPacket(bit);
break; break;
default: default:
processStream(bit); processNone(bit);
break; break;
} }
} }
@ -74,15 +74,15 @@ void CM17RX::processNone(bool bit)
if (bit) if (bit)
m_bitBuffer |= 0x01U; m_bitBuffer |= 0x01U;
// Fuzzy matching of the header sync bit sequence // Fuzzy matching of the link setup sync bit sequence
if (countBits16(m_bitBuffer ^ M17_LINK_SETUP_SYNC_BITS) <= MAX_SYNC_BIT_START_ERRS) { if (countBits16(m_bitBuffer ^ M17_LINK_SETUP_SYNC_BITS) <= MAX_SYNC_BIT_START_ERRS) {
DEBUG1("M17RX: header sync found in None"); DEBUG1("M17RX: link setup sync found in None");
for (uint8_t i = 0U; i < M17_SYNC_BYTES_LENGTH; i++) for (uint8_t i = 0U; i < M17_SYNC_BYTES_LENGTH; i++)
m_buffer[i] = M17_LINK_SETUP_SYNC_BYTES[i]; m_buffer[i] = M17_LINK_SETUP_SYNC_BYTES[i];
m_lostCount = MAX_SYNC_FRAMES; m_lostCount = MAX_SYNC_FRAMES;
m_bufferPtr = M17_SYNC_LENGTH_BITS; m_bufferPtr = M17_SYNC_LENGTH_BITS;
m_state = M17RXS_HEADER; m_state = M17RXS_LINK_SETUP;
io.setDecode(true); io.setDecode(true);
} }
@ -114,7 +114,7 @@ void CM17RX::processNone(bool bit)
} }
} }
void CM17RX::processHeader(bool bit) void CM17RX::processLinkSetup(bool bit)
{ {
m_bitBuffer <<= 1; m_bitBuffer <<= 1;
if (bit) if (bit)
@ -126,16 +126,6 @@ void CM17RX::processHeader(bool bit)
if (m_bufferPtr > M17_FRAME_LENGTH_BITS) if (m_bufferPtr > M17_FRAME_LENGTH_BITS)
reset(); reset();
// Only search for a sync in the right place +-2 symbols
if (m_bufferPtr >= (M17_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (M17_SYNC_LENGTH_BITS + 2U)) {
// Fuzzy matching of the data sync bit sequence
if (countBits16(m_bitBuffer ^ M17_LINK_SETUP_SYNC_BITS) <= MAX_SYNC_BIT_RUN_ERRS) {
DEBUG2("M17RX: found header sync in Data, pos", m_bufferPtr - M17_SYNC_LENGTH_BITS);
m_lostCount = MAX_SYNC_FRAMES;
m_bufferPtr = M17_SYNC_LENGTH_BITS;
}
}
// Send a data frame to the host if the required number of bits have been received // Send a data frame to the host if the required number of bits have been received
if (m_bufferPtr == M17_FRAME_LENGTH_BITS) { if (m_bufferPtr == M17_FRAME_LENGTH_BITS) {
m_lostCount--; m_lostCount--;
@ -145,9 +135,7 @@ void CM17RX::processHeader(bool bit)
writeRSSIHeader(m_outBuffer); writeRSSIHeader(m_outBuffer);
// Start the next frame, but we don't know the type // Start the next frame, but we don't know the type
::memset(m_outBuffer, 0x00U, M17_FRAME_LENGTH_BYTES + 3U); reset();
m_state = M17RXS_NONE;
m_bufferPtr = 0U;
} }
} }
@ -167,7 +155,7 @@ void CM17RX::processStream(bool bit)
if (m_bufferPtr >= (M17_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (M17_SYNC_LENGTH_BITS + 2U)) { if (m_bufferPtr >= (M17_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (M17_SYNC_LENGTH_BITS + 2U)) {
// Fuzzy matching of the stream sync bit sequence // Fuzzy matching of the stream sync bit sequence
if (countBits16(m_bitBuffer ^ M17_STREAM_SYNC_BITS) <= MAX_SYNC_BIT_RUN_ERRS) { if (countBits16(m_bitBuffer ^ M17_STREAM_SYNC_BITS) <= MAX_SYNC_BIT_RUN_ERRS) {
DEBUG2("M17RX: found stream sync in Data, pos", m_bufferPtr - M17_SYNC_LENGTH_BITS); DEBUG2("M17RX: found stream sync, pos", m_bufferPtr - M17_SYNC_LENGTH_BITS);
m_lostCount = MAX_SYNC_FRAMES; m_lostCount = MAX_SYNC_FRAMES;
m_bufferPtr = M17_SYNC_LENGTH_BITS; m_bufferPtr = M17_SYNC_LENGTH_BITS;
} }
@ -211,7 +199,7 @@ void CM17RX::processPacket(bool bit)
if (m_bufferPtr >= (M17_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (M17_SYNC_LENGTH_BITS + 2U)) { if (m_bufferPtr >= (M17_SYNC_LENGTH_BITS - 2U) && m_bufferPtr <= (M17_SYNC_LENGTH_BITS + 2U)) {
// Fuzzy matching of the packet sync bit sequence // Fuzzy matching of the packet sync bit sequence
if (countBits16(m_bitBuffer ^ M17_PACKET_SYNC_BITS) <= MAX_SYNC_BIT_RUN_ERRS) { if (countBits16(m_bitBuffer ^ M17_PACKET_SYNC_BITS) <= MAX_SYNC_BIT_RUN_ERRS) {
DEBUG2("M17RX: found packet sync in Data, pos", m_bufferPtr - M17_SYNC_LENGTH_BITS); DEBUG2("M17RX: found packet sync, pos", m_bufferPtr - M17_SYNC_LENGTH_BITS);
m_lostCount = MAX_SYNC_FRAMES; m_lostCount = MAX_SYNC_FRAMES;
m_bufferPtr = M17_SYNC_LENGTH_BITS; m_bufferPtr = M17_SYNC_LENGTH_BITS;
} }

4
M17RX.h
View file

@ -24,7 +24,7 @@
enum M17RX_STATE { enum M17RX_STATE {
M17RXS_NONE, M17RXS_NONE,
M17RXS_HEADER, M17RXS_LINK_SETUP,
M17RXS_STREAM, M17RXS_STREAM,
M17RXS_PACKET M17RXS_PACKET
}; };
@ -46,7 +46,7 @@ private:
uint16_t m_lostCount; uint16_t m_lostCount;
void processNone(bool bit); void processNone(bool bit);
void processHeader(bool bit); void processLinkSetup(bool bit);
void processStream(bool bit); void processStream(bool bit);
void processPacket(bool bit); void processPacket(bool bit);
void writeRSSIHeader(uint8_t* data); void writeRSSIHeader(uint8_t* data);

2
version.h
View file

@ -25,7 +25,7 @@
#define VER_MAJOR "1" #define VER_MAJOR "1"
#define VER_MINOR "5" #define VER_MINOR "5"
#define VER_REV "2" #define VER_REV "2"
#define VERSION_DATE "20210101" #define VERSION_DATE "20210102"
#if defined(ZUMSPOT_ADF7021) #if defined(ZUMSPOT_ADF7021)
#define BOARD_INFO "ZUMspot" #define BOARD_INFO "ZUMspot"