DShot ESC Communication Library for Arduino

Overview

This library provides a simple implementation of the DShot protocol for communicating with electronic speed controllers (ESCs) using an Arduino. DShot is a digital protocol used for high-speed and precise control of brushless motors, commonly used in drones and RC vehicles.

Requirements

• For now the library works only with atmega328 (or other boards with 16 MHz clock) and DShot300 protocol

Usage

Wiring

Connect the signal wires of the ESC to the appropriate Arduino digital pins.

Function Descriptions

void dshot_init(int8_t pin);

This function initializes the DShot communication on the specified pin by sending a series of 0-bit frames to the ESC.

• pin: The digital output pin connected to the ESC signal wire.

void dshot_run(int16_t throttle, int8_t pin);

This function sends a 16-bit DShot command containing the throttle value and CRC checksum.

• throttle: 11-bit throttle value (0-2047), where 48-2047 represents valid throttle values, and 0-47 are special commands.

Code Example

#include <Arduino.h>
#include "Dshot.h"

void setup() {
    dshot_init(9); // Initialize DShot communication on pin 9
}

void loop() {
    int16_t throttle = 1046;
    dshot_run(throttle, 9);  // Send DShot frame to pin 9
    delay(1);
}

Timing Details

• HIGH signal duration:
  • 1-bit: ~2.55 µs high, 0.8 µs low
  • 0-bit: ~1.25 µs high, 2.05 µs low
• Cycle time: ~3.33 µs per bit

CRC Calculation

A 4-bit CRC checksum is appended to each DShot command to ensure data integrity. It is calculated using:

uint8_t crc = (value ^ (value >> 4) ^ (value >> 8)) & 0x0F;

Notes

• The library uses direct register access (PORTx and DDRx) for fast execution.
• Interrupts are disabled during communication to ensure precise timing.
• More details: https://brushlesswhoop.com/dshot-and-bidirectional-dshot/

Tested it on BLS 55A 4in1 ESC from Speedybee and it works fine.