Dshot Usage Notes
Dshot Usage Notes — Usage information about the
protocol and the code module
Protocol Description
Dshot (Digital shot) is a digital protocol for
Flight-Controller(FC)-to-Electronic-Speed-Controller(ESC) communication used in
unmanned aerial vehicle (UAV) applications. Dshot offers CRC checksum, a higher
resolution than traditional protocols and does not require ESC calibration. This
code module is designed for Dshot 150, Dshot 300, Dshot 600 and Dshot 1200, which
have different transmission frequencies.
The transmission of one data packet contains 16 bits, where each bit is
represented by one pulse. The signals for 0 and 1 are distinguished by their
different high times, and the bit period is constant for each protocol mode.
The Dshot data packet consists of these pulses:
Throttle
The throttle contains 11-bit data sent from the flight controller to the ESC.
It gives a resolution of 2048 values. The values 0-47 are reserved, 1-47 are for
the telemetry settings, and 0 is for disarming.
Telemetry Bit
The telemetry bit is set if the flight controller signals a telemetry update
to the ESC. The throttle contains the appropriate values as stated above. The
telemetry update uses a separate return channel.
Checksum
The checksum comprises a 4-bit CRC value. The checksum is calculated according
to the Dshot specification, using a polynomial according to the Dshot protocol
specifications, and is calculated over the throttle and telemetry request
bit.
Dshot modes
The Dshot family consists of multiple protocol types, which all differ in bit
rate.
Pulse Sequence
In Dshot, the length of the high time indicates if the transmitted bit is a 0
or a 1. The high times according to the Dshot modes are stated in the table
below.
