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DShotRMT
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...adding return values 

...prepare for proper debug
This commit is contained in:
Wastl Kraus 2025-08-03 22:15:38 +02:00
parent e4a5e1f304
commit 330d06363a
3 changed files with 62 additions and 50 deletions
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99
DShotRMT.cpp
View File

@ -9,7 +9,8 @@
#include "DShotRMT.h"
// --- DShot Timings ---
const dshot_timing_t DSHOT_TIMINGS[] = {
// frame_length_us, ticks_per_bit, ticks_one_high, ticks_zero_high, ticks_zero_low, ticks_one_low
constexpr dshot_timing_t DSHOT_TIMINGS[] = {
{0, 0, 0, 0, 0, 0}, // DSHOT_OFF
{128, 64, 48, 24, 40, 16}, // DSHOT150
{64, 32, 24, 12, 20, 8}, // DSHOT300
@ -18,15 +19,16 @@ const dshot_timing_t DSHOT_TIMINGS[] = {
};
//
DShotRMT::DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool is_bidirectional)
: _gpio(gpio), _mode(mode)
, _is_bidirectional(is_bidirectional)
, _timing_config(DSHOT_TIMINGS[mode])
, _rmt_tx_channel(nullptr)
, _rmt_rx_channel(nullptr)
, _dshot_encoder(nullptr)
, _last_erpm(0)
, _last_transmission_time(0)
DShotRMT::DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool is_bidirectional):
_gpio(gpio),
_mode(mode),
_is_bidirectional(is_bidirectional),
_timing_config(DSHOT_TIMINGS[mode]),
_rmt_tx_channel(nullptr),
_rmt_rx_channel(nullptr),
_dshot_encoder(nullptr),
_last_erpm(0),
_last_transmission_time(0)
{
// Calculate frame time including switch time
_frame_time_us = _timing_config.frame_length_us + DSHOT_SWITCH_TIME;
@ -38,21 +40,24 @@ DShotRMT::DShotRMT(gpio_num_t gpio, dshot_mode_t mode, bool is_bidirectional)
}
}
//
// Init DShotRMT
bool DShotRMT::begin()
{
// Init TX Channel
if (!_initTXChannel())
{
Serial.println("Failed to initialize TX channel");
return DSHOT_ERROR;
}
// Init RX Channel
if (!_initRXChannel() && _is_bidirectional)
{
Serial.println("Failed to initialize RX channel");
return DSHOT_ERROR;
}
// Init DShot Decoder
if (!_initDShotEncoder())
{
Serial.println("Failed to initialize encoder");
@ -77,6 +82,8 @@ bool DShotRMT::setThrottle(uint16_t throttle)
{
return DSHOT_ERROR;
}
return DSHOT_OK;
}
//
@ -94,6 +101,7 @@ bool DShotRMT::sendDShotCommand(uint16_t command)
{
return DSHOT_ERROR;
}
return DSHOT_OK;
}
//
@ -180,28 +188,30 @@ bool DShotRMT::_initDShotEncoder()
return rmt_new_copy_encoder(&encoder_config, &_dshot_encoder) == 0;
}
//
bool DShotRMT::_sendDShotFrame(const dshot_packet_t &packet)
// Use RMT to transmit a prepared DShot packet and returns it
uint16_t DShotRMT::_sendDShotFrame(const dshot_packet_t &packet)
{
//
if (!_timer_signal())
{
return DSHOT_ERROR;
}
// Encodes packet directly into RMT Buffer
rmt_symbol_word_t tx_symbols[DSHOT_BITS_PER_FRAME];
_encodeDShotFrame(packet, tx_symbols);
//
if (!_timer_signal())
{
return DSHOT_NULL_PACKET;
}
// Trigger RMT Transmit
if (rmt_transmit(_rmt_tx_channel, _dshot_encoder, tx_symbols, DSHOT_SYMBOLS_SIZE, &_transmit_config) != 0)
{
Serial.println("Failed to transmit DShot packet");
return DSHOT_ERROR;
return DSHOT_NULL_PACKET;
}
// Time Stamp
_timer_reset();
return DSHOT_OK;
return _assembleDShotFrame(packet);
}
//
@ -228,33 +238,32 @@ uint16_t DShotRMT::_assembleDShotFrame(const dshot_packet_t &packet)
}
//
void DShotRMT::_encodeDShotFrame(const dshot_packet_t &packet, rmt_symbol_word_t *symbols)
bool DShotRMT::_encodeDShotFrame(const dshot_packet_t& packet, rmt_symbol_word_t* symbols)
{
{
// Encoding to "raw" DShot Packet
uint16_t frame_bits = _assembleDShotFrame(packet);
// Encoding to "raw" DShot Packet
uint16_t frame_bits = _assembleDShotFrame(packet);
// Convert the parsed dshot frame to rmt_tx data
for (int i = 0; i < DSHOT_BITS_PER_FRAME; i++)
// Convert the parsed dshot frame to rmt_tx data
for (int i = 0; i < DSHOT_BITS_PER_FRAME; i++)
{
// Encode RMT symbols bitwise (MSB first) - tricky
bool bit = (frame_bits >> (DSHOT_BITS_PER_FRAME - 1 - i)) & 0b0000000000000001;
if (_is_bidirectional)
{
// Encode RMT symbols bitwise (MSB first) - tricky
bool bit = (frame_bits >> (DSHOT_BITS_PER_FRAME - 1 - i)) & 0b0000000000000001;
if (_is_bidirectional)
{
symbols[i].level0 = 0;
symbols[i].duration0 = bit ? _timing_config.ticks_one_high : _timing_config.ticks_zero_high;
symbols[i].level1 = 1;
symbols[i].duration1 = bit ? _timing_config.ticks_one_low : _timing_config.ticks_zero_low;
}
else
{
symbols[i].level0 = 1;
symbols[i].duration0 = bit ? _timing_config.ticks_one_high : _timing_config.ticks_zero_high;
symbols[i].level1 = 0;
symbols[i].duration1 = bit ? _timing_config.ticks_one_low : _timing_config.ticks_zero_low;
}
symbols[i].level0 = 0;
symbols[i].duration0 = bit ? _timing_config.ticks_one_high : _timing_config.ticks_zero_high;
symbols[i].level1 = 1;
symbols[i].duration1 = bit ? _timing_config.ticks_one_low : _timing_config.ticks_zero_low;
}
else
{
symbols[i].level0 = 1;
symbols[i].duration0 = bit ? _timing_config.ticks_one_high : _timing_config.ticks_zero_high;
symbols[i].level1 = 0;
symbols[i].duration1 = bit ? _timing_config.ticks_one_low : _timing_config.ticks_zero_low;
}
}
return DSHOT_OK;
}
//
@ -298,7 +307,9 @@ bool DShotRMT::_timer_signal()
}
//
void DShotRMT::_timer_reset()
bool DShotRMT::_timer_reset()
{
// Timestamp update
_last_transmission_time = micros();
return DSHOT_OK;
}

9
DShotRMT.h
View File

@ -24,7 +24,7 @@ static constexpr uint16_t DSHOT_THROTTLE_MIN = 48;
static constexpr uint16_t DSHOT_THROTTLE_MAX = 2047;
static constexpr uint8_t DSHOT_BITS_PER_FRAME = 16;
static constexpr uint8_t DSHOT_SWITCH_TIME = 21;
static constexpr uint8_t DSHOT_SWITCH_TIME = 300; // 30us
static constexpr uint16_t DSHOT_NULL_PACKET = 0b0000000000000000;
// --- RMT Config Constants ---
@ -66,6 +66,7 @@ typedef struct
// --- DShot Timing Config ---
extern const dshot_timing_t DSHOT_TIMINGS[];
//
class DShotRMT
{
public:
@ -123,12 +124,12 @@ private:
bool _initRXChannel();
bool _initDShotEncoder();
uint16_t _sendDShotFrame(const dshot_packet_t &packet);
uint16_t _calculateCRC(const dshot_packet_t &packet);
uint16_t _assembleDShotFrame(const dshot_packet_t &packet);
void _encodeDShotFrame(const dshot_packet_t &packet, rmt_symbol_word_t *symbols);
bool _encodeDShotFrame(const dshot_packet_t &packet, rmt_symbol_word_t *symbols);
uint16_t _decodeDShotFrame(const rmt_symbol_word_t *symbols, size_t symbol_count);
bool _sendDShotFrame(const dshot_packet_t &packet);
bool _timer_signal();
void _timer_reset();
bool _timer_reset();
};

4
examples/dshot300/dshot300.ino
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@ -10,11 +10,11 @@
#include <DShotRMT.h>
// USB serial port settings
static constexpr auto &USB_SERIAL = Serial0;
static constexpr HardwareSerial &USB_SERIAL = Serial0;
static constexpr uint32_t USB_SERIAL_BAUD = 115200;
// Motor configuration
static constexpr gpio_num_t MOTOR01_PIN = PIN_UART2_RX;
static constexpr gpio_num_t MOTOR01_PIN = GPIO_NUM_17;
static constexpr dshot_mode_t DSHOT_MODE = DSHOT300;
// BiDirectional DShot Support (default: false)