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DShotRMT
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...modular functions 

...crc calculation and paket building in seperate functions now
This commit is contained in:
Wastl Kraus 2025-06-17 20:56:50 +02:00
parent 8557930d3e
commit 1c8a0ed572
2 changed files with 41 additions and 8 deletions
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42
DShotRMT.cpp
View File

@ -73,14 +73,8 @@ void DShotRMT::setThrottle(uint16_t throttle)
_lastThrottle = throttle;
// Assemble raw DShot packet and compute checksum
_tx_packet = (throttle << 1) | (_isBidirectional ? 1 : 0);
uint16_t crc = _isBidirectional
? (~(_tx_packet ^ (_tx_packet >> 4) ^ (_tx_packet >> 8))) & 0x0F
: (_tx_packet ^ (_tx_packet >> 4) ^ (_tx_packet >> 8)) & 0x0F;
_tx_packet = (_tx_packet << 4) | crc;
// Convert throttle value to DShot Paket Format
_tx_packet = assambleDShotPaket(_lastThrottle);
// Encode RMT symbols
size_t count = 0;
@ -167,6 +161,38 @@ uint32_t DShotRMT::getMotorRPM(uint8_t magnet_count)
return rpm;
}
// Calculate CRC for DShot Paket
uint16_t DShotRMT::calculateCRC(uint16_t dshot_packet)
{
// Clear container before new calculation
_packet_crc = DSHOT_NULL_PACKET;
// CRC is inverted for biDirectional DSHot
_packet_crc = _isBidirectional
? (~(dshot_packet ^ (dshot_packet >> 4) ^ (dshot_packet >> 8))) & 0x0F
: (dshot_packet ^ (dshot_packet >> 4) ^ (dshot_packet >> 8)) & 0x0F;
return _packet_crc;
}
// Assamble DShot Paket (10 bit throttle + 1 bit telemetry request + 4 bit crc)
uint16_t DShotRMT::assambleDShotPaket(uint16_t value)
{
// Clear container
_tx_packet = DSHOT_NULL_PACKET;
// dummy 10bit convertion
_tx_packet = value & 0b0000011111111111;
// Assemble raw DShot packet and add checksum
_tx_packet = (value << 1) | (_isBidirectional ? 1 : 0);
_packet_crc = calculateCRC(_tx_packet);
_tx_packet = (_tx_packet << 4) | _packet_crc;
return _tx_packet;
}
// --- Encode DShot TX Frame ---
// Converts a 16-bit packet into a valid DShot Frame for RMT
void DShotRMT::encodeDShotTX(uint16_t dshot_packet, rmt_symbol_word_t *symbols, size_t &count)

7
DShotRMT.h
View File

@ -67,6 +67,12 @@ public:
dshot_mode_t getDShotMode() const { return _mode; }
private:
// Calculate the checksum for throttle value
uint16_t calculateCRC(uint16_t dshot_packet);
// Assamble DShot Paket (10 bit throttle + 1 bit telemetry request + 4 bit crc)
uint16_t assambleDShotPaket(uint16_t value);
// Converts a 16-bit DShot packet into RMT symbols and appends pause
void encodeDShotTX(uint16_t dshot_packet, rmt_symbol_word_t *symbols, size_t &count);
@ -79,6 +85,7 @@ private:
uint16_t _lastThrottle = DSHOT_FULL_PACKET;
uint16_t _received_packet = DSHOT_NULL_PACKET;
uint16_t _tx_packet = DSHOT_NULL_PACKET;
uint16_t _packet_crc = DSHOT_NULL_PACKET;
// --- RMT Channel ---
rmt_channel_handle_t _rmt_rx_channel = nullptr;