DShot ESP32 Library using RMT (Rewrite for ESP-IDF 5)

This is a complete rewrite of the original DShotRMT library to support the new ESP-IDF 5 RMT encoder API (rmt_tx.h).
The library sends continuous DShot frames with a configurable pause between them and supports all standard DShot modes (150, 300, 600).

The old Version without encoding (rmt.h) is still available by using "oldAPI" Branch.

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The DShot Protocol

The DShot protocol transmits 16-bit packets to brushless ESCs:

• 11-bit throttle value
• 1-bit telemetry request
• 4-bit checksum

Data is transmitted MSB-first. Pulse timing depends on the selected DShot mode.

DSHOT	Bitrate	TH1	TH0	Bit Time (µs)	Frame Time (µs)
150	150 kbit/s	5.00	2.50	6.67	~106.72
300	300 kbit/s	2.50	1.25	3.33	~53.28
600	600 kbit/s	1.25	0.625	1.67	~26.72

Each frame is followed by a 21-bit time pause at low level. This helps ESCs detect separate frames.

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Checksum Calculation

The checksum is calculated over the first 12 bits (throttle + telemetry):

crc = (value ^ (value >> 4) ^ (value >> 8)) & 0x0F;

For Bidirectional DShot (not yet implemented), the CRC is inverted:

crc = (~(value ^ (value >> 4) ^ (value >> 8))) & 0x0F;

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RMT on the ESP32

The RMT peripheral on the ESP32 is perfect for generating precise time-based signals like DShot.

Advantages:

• Hardware-timed pulses
• CPU-independent signal generation
• Loop mode with inter-frame pause
• Reliable under system load

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About This Library

This C++ library provides a simple class to generate DShot signals using any RMT-capable GPIO.
It uses a copy_encoder to continuously send a prebuilt symbol buffer. New throttle values are applied only when they change.

Supported Modes:

• DSHOT150
• DSHOT300 (default)
• DSHOT600

Frame Structure:

• 16-bit DShot data
• 21-bit times worth of pause (LOW)

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References

• DSHOT – the missing Handbook
• DSHOT in the Dark
• ESP32 Technical Reference Manual

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License

MIT License – see LICENSE

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Author

Wastl Kraus
GitHub: @derdoktor667
Website: wir-sind-die-matrix.de