ESC Firmware and Protocols Overview

by Oscar

There are several types of ESC protocol and ESC firmware available for quadcopter. In this article we will give a little history and explain the technical differences. Most importantly I want to try and clear up some of the confusion beginners experience from such a wide selection.

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When I started in the hobby, connecting an ESC to a flight controller was pretty straight-forward. But now there are much more to consider: ESC settings, protocols, firmware etc. All these options can be confusing and overwhelming for someone just starting out in this hobby.

Check out this guide about how to choose ESC for FPV drones

ESC Firmware

ESC firmware is the software that runs on every ESC. It determines what ESC settings you can change, which protocols are supported, and what configuration interface can be used. The firmware that an ESC is allowed to use depends on the hardware.

Here is a list of the different ESC firmware available for mini quad:

Two of the earliest options for open source ESC firmware were SimonK and BLHeli, and these firmware were used on the majority of ESC’s until around 2015. Since then BLHeli has taken over the market due its more user-friendly interface and consistent development.

Check out the differences between BLHeli and SimonK.

As ESC technology continues to evolve, newer BLHeli firmware is being written specifically for the advances in hardware.

In 2016, BLHeli_S was released as an upgrade to the BLHeli firmware for the BusyBee processors (BB1 & BB2 chips).

In 2017, the 3rd generation BLHeli, BLHeli_32, was created to take full advantage of the additional processing power available from 32-bit processors we are beginning to see on newer ESC’s.

Nowadays, all ESC’s come with firmware pre-installed, most commonly BLHeli_S or BLHeli_32 depending on the hardware. Anyway this should be clearly stated in the product description.

BLHeli_S and BLHeli_32 ESC’s are what I personally would recommend these days. They have the best performance and cutting edge features, and still being updated on a regular basis.

For BLHeli_S ESC, you can optionally flash Bluejay firmware to unlock certain features that are only available on BLHeli_32 ESC, such as bi-directional DShot and custom startup sound. It truly brings the performance to the level of the more expensive BLHeli_32 ESC.

In 2020, AM32 is released. It’s a open source firmware that could be the BLHeli_32 alternative. Some latest ESC are already shipped with AM32 firmware. Learn more about AM32 here:

ESC Protocols

ESC Protocols are the “languages” that the flight controller and ESC use to communicate, for example, how fast the motor should be spinning.

Here are all the ESC protocols currently available for a Betaflight FPV drone, and their respective signal width – the time it takes to send one data packet (click the links for more info):

ESC Protocol Speed

ESC Protocol Speed

Before 2015, there was only one ESC protocol, standard PWM, but as hardware was getting better, faster protocols became possible: Oneshot125, Oneshot42 and Multishot. These protocols are all analog signals similar to standard PWM, but much faster (less delay). These protocols are synced to the PID loop in the flight controller to reduce jitters, improve performance and reduce delay between stick inputs and the reaction of the craft.

DShot is the latest ESC protocol which is a digital signal. It’s the future of ESC protocol in my opinion because of its better reliability and performance, and the ability of sending not only motor speed, but specific commands to the ESC’s. directional DShot is also possible, which means the ESC and FC can have a two-way communication, the ESC can send motor RPM data back to the FC, it made RPM filtering and other advanced PID features like dynamic idle possible.

Between DShot300/600/1200, the faster protocol is better at latency, but is not always better as it’s actually more prone to corrupted packets. It’s suggested by Betaflight that we should select a suitable DShot speed based on the PID Loop Frequency.

  • 2K PID Loop Frequency, use DShot150
  • 4K PID Loop Frequency, use DShot300
  • 8K PID Loop Frequency, use DShot600

And realistically, the latency of the different DShot is in micro seconds, IMO the impact on performance is probably not meaningful, if so I would love to see some proof. And the increased chance of packet corruption might have a bigger impact.

I hope this guide gave you an overview of all the ESC software and protocols. Please don’t hesitate to leave me a question or comment.

Edit History

  • July 2017 – Article created
  • Oct 2022 – Added Bluejay/AM32, updated DShot recommendation

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Arthur 10th January 2023 - 8:08 am

Hi Oscar,
My nazgul5 v2 runs at 3,2k, but by default the motor protocol is dshot600.

Looking at you table above, i should run dshot300. Is there something i overlook?

Kind regards,


Oscar 10th January 2023 - 11:16 am

Yea you should be running DShot300.

Kristian 28th November 2022 - 9:18 pm

Hello … quick question.

It seams that i have a ESC that failed manufacturer activation , is it fixable ?

Thank you :D

Oscar 29th November 2022 - 12:07 am

what ESC? which software you using for activation?

Darryl White 28th October 2022 - 6:54 pm

Hi Oscar, I’m not an expert on esc”s but I am having a problem. Before I assemble the several builds I’ve made I do a “dry run ” with the stack,receiver, and the motors I plan to use all hooked up to betaflight Before I put them into the frame to work out a “bugs ” before “surgery “. I recently purchased 2 spare skystars 4 in 1 esc’s that were listed as identical to the stacks I ‘ve always bought together. I used the NEW esc with a year old skystars FC F722HD,connected to betaflight, erased and re-flashed and re-programmed every parameter and got all the proper “musical tones “, HOWEVER, when I disconnect and power up I get 2 immediate “all ok musical tones ” in succession. I’m afraid to continue the build for fear it might take off and fly to the moon ! DO you think this double ” OK TONE ” indicates that I used a BLHELI S esc instead of a BLHELI_32 or just some other error ? Skystars did not indicate if this spare esc was BLHELI S or BLHELI_32 so I tried to use your tutorial on “FC pass thru esc flashing ” to try and determine this but got a error that the com port won’t open. When I power the set-up WHILE CONNECTED to betaflight I get the proper 1″ all ok musical tone” but when I disconnect and power-up I get the DOUBLE ” all ok musical tone “. DO you have any suggestions ? Thanks, Darryl

timucin demiralp 10th October 2022 - 8:50 am

I am always using Multishot with my 7 inch with INAV 5.1. It is very smooth and works great for me. I have 3questions.
1-What is the PID loop frequency for Multishot?
2-Is there any benefit having H7 or F7 over F4 if you are using only with Multishot?
3-Am I missing any critical feature with Multishot?

Brahadeeswar Radhakrishna 23rd September 2021 - 2:53 pm

Flashed my esc with wrong to revert it back as iam not aware of orginal firmware.motor not spining but there is beep sound..pls do help

RONALD KENNEDY 16th July 2021 - 4:21 pm

This is My First build using HobbyWing 60amp 4 in 1 esc that supposed to support all these protocols My build is strickly a iNav system to fly around and stop circle and take video’s etc i’m asking your opinion cause i can’t find it anywhere that suggests what D-Shot i should use to have for this 10in build using 880kv motors, I have only Flew arducopter stuff this is all new to me I’m Lost. Thankyou. R.K

mertz ( mertz ) Nicolas 8th July 2021 - 1:39 pm

bonjour , je suis occupé a me monter un quad avec une T-MOTOR F722 mais je ne sais pas quel protocole je dois sélectionné sur betaflight
d’avance merci pour votre aide

Sean Andreas 12th July 2020 - 7:10 pm

Hey there, maybe you can help me. I have a Diatone mamba f411nano stack. The esc firmware says bl_heli suite. My question is can I use bl_heli configurator to flash my ESCs. Or do I need bl heli suite? I’ve been trying with the appropriate dshot protocols in beta flight I’ve also tested a few other protocols and bl heli version updates. I’ve tested the ESCs with a multimeter to make sure they’re not bad. But only motor 1 starts up spinning when armed. The other three motors just twitch and then the drone beeps and the motors stop. Same thing in beta flight motors tab. Could this be because I’m not using bl_heli Suite? Any help would appreciated.

Oscar 12th July 2020 - 11:29 pm

Yes, BLHeli Configurator still works on BLHeli_S ESC.
Have you tried other protocols? Like Oneshot? You can try flashing an older firmware version see if that fixes it.
Note that BLHeli_S only supports DShot600, if you use Bidirectional DShot, use DShot300.

Jesse 2nd September 2022 - 5:44 am

Awesome info. I have the Aio F4 1S spi rx 5 amp brushless FC and broke two motors in10 batteries one the same ESC… Anything obvious would cause that? Thanks in advance

Mike Miller 30th June 2020 - 6:30 pm

Hello, I have an esc that is set to Oneshot125, but is Dshot capable. How do you actually change the input protocol of the esc?


Oscar 4th July 2020 - 3:39 pm

You can do that in Betaflight Configuration tab, you can select ESC protocol you want to use. Your ESC will detect it automatically so no change is required on the ESC side.

Edu 20th January 2020 - 2:28 pm

Hello. You could tell me if I can use together 4 esc dji 420S 20A and 2 simonk 30A with my Naza V2? Thanks a lot. You have a very interesting website.

Saijin_Naib 17th January 2020 - 9:05 pm


Do you think/know of any concrete improvements in ESC performance from roughly 2011-era SimonK to latest BLHeli 14.9 (2016)?

I’m trying to collect information about possibly cross-flashing/updating a legacy ESC that is still deployed fairly wide.

Thanks for all your incredible information!

BRIGZY FPV 11th January 2020 - 9:50 pm

Thanks for your info, very helpful, always!

I just wanted to flash and set my motor direction on my GT R349 HD quads, I just put a brand new ESC in my older one, stupidly I went out and tested it LOS and it went bezerk. I didn’t stop to think the ESC needed setting up but obviously it did. All my motors were turning clockwise, I have flashed all ESC’s & changed motors 2 and 3 to reversed and flew it LOS and all good. My question is, why would I use “BLHELI Suite” rather than just the “BLHELI 1.2” program I just installed? It appears to be a very basic version but does everything I need. Should I be using the “Suite Version”? Sorry, a bit confused.

Thx Brigzy FPV.

Oscar 13th January 2020 - 4:42 pm

BLHeli is the name of the firwmare, and BLHeliSuite is the name of the configurator…
1.2 is a very old version indeed, but if that works for you then there is no need to update, let alone the old hardware might not support the new firmware anyway.

curt bixel 25th November 2019 - 12:18 am


Thanks for your responses above.

As far as the “Tank Drive” question, tank drive just means that the combat robot has two wheels, and to pivot left, you put the left wheel in reverse and the right wheel in forward. To go forward, you just run both wheels forward.

I am curious why one side always seems more powerful than the other.

On another note, we are finding that with our weapon, which is 5 pounds of steel spinning at 4000 rpm, the braking or the
“damped mode” is causing a regenerated current that is damaging our speed controllers. The wires come unsoldered and components have melted free from the board. As long as we are careful to allow the weapon to spin down by itself, the ESC handles things quite well. But, making sure students reduce throttle from 100% to a much lower percentage, without ever hitting zero, or going to negative throttle, risks our ESC’s.

Do you have a suggestion for a workaround using the Flycolor X-cross 50 amp? I have tried to put it in “normal” mode as far as motor direction, but for some reason, the system will not work in this configuration. The motor just beeps, even though it is not yet attached to the weapon.

Finally, is there another speed controller you might suggest that is small, can handle 50 amps, and can be set so as to not try to slow the weapon down with braking or with damping?

curt bixel 10th November 2019 - 4:52 pm


We are using the Flycolor X-cross 50 amp ESC’s for combat robotics. They are small, very reliable, and seem to be able to handle well in excess of 50 amps. We are using BLHeliSuite32 and configure our ESC’s using the interface available for the Macintosh computer. I have a few questions I have not really been able to answer after a few hours of researching on the internet. Would you be able to answer any of these?

One – How do I know if I am using MultiShot, DShot, or something else? I can’t really see any way to tell by looking through the menu’s on BLHeliSuite.

Two – Is there any way to do current limiting with the FlyColor ESC and BLHeli?

Three – We usually use “Tank Drive” and almost without fail, one side is more powerful than the other. Is there any way to adjust the power by working with the settings on the ESC? I can see “ramp up power” and “maximum” acceleration, but neither of these seem to be designed to do what I am trying to do.

Four – We have “braking” turned off, but the motor is still clearly doing some braking. Any suggestions there?

We are using an Arduino Nano and a USB cable as an interface with the Arduino 4-way interface.

Oscar 18th November 2019 - 6:25 pm

1. it’s a BLHeli_32 ESC right? if so it should support DShot and Multishot
2. If it has a current sensor then yes, if not then you can’t; setting in BLHeliSuite_32
3. not sure what you mean by tank drive
4. you can’t turn off “active braking” on BLHeli32 ESC

Brian Evans 4th July 2019 - 11:50 am

Hi Oscar
How to flash updated firmware onto an ESC?
I just used the default one which was 40-H and now my motors are acting strangely (spinning very fast at zero throttle).
My ESC is Mamba 4-in1 F40 40A ESC.
Any advice is greatly appreciated!

Oscar 15th July 2019 - 4:40 pm Reply
Frantisek Dvorak 19th June 2019 - 10:59 pm

Luis Inciarte

I was trying to make Naze32 passthrough work for 2 days – and I made it to work.

Way how I did it:
– FC downgraded to BF 3.1.7
– enabled softserial passthrough in BF configurator, enabled the softserial in ports tab
– newest BLheli – silabs blheli bootloader (cleanflight)
– done

It is possible that with enabled softserial passthrough it will work even in newer BF

John Gatza 1st April 2019 - 12:17 am

Hello Oscar – excellent writeup on escs and control protocol. Thank you.

I’m building a quadcopter with Pixhawk 4 and I used airbot wraith 32 v2 escs since they seem to have the latest feature capability.

Thinking Pixhawk 4 was also latest technology I figured this would work but I’m having trouble.

I can program the eSC non pass through but cannot get the motors to move….using qgroundcontrol and mission planner. All else works and I’m disarmed. Any thoughts?

Are these ESCs compatible with my Pixhawk 4? Thanks again.

Luis Inciarte 21st May 2018 - 4:08 am

Helllo sir,

I would like to have your suggestion about an issue that I am having to connect my ESCs using BLHeliSuite/BLHeliSuite32. The program is not reading my ESCs. Here is the info:

ESC = Thriverline Acrotor BLHeli-32 ESC 30A 32Bit Brushless ESC Support 2-4S Dshot1200 (30A)
FC = Readytosky Naze32 Rev6 Full Version loaded with Firmware CL V2.3.2
Motors = EMAX RS2205S 2600KV Brushless Motor

I just want to reverse 2 of the motors from CW to CCW.

Thanks in advance

Oscar 22nd May 2018 - 3:23 pm

I don’t think F1 flight cotnrollers (Naze32) supports ESC passthrough connection.
You will need at least an F3 FC, and flash it with the latest Betaflight firmware.
To reverse motors roation, just swap two of the wires.

Marcos Santana 1st November 2018 - 3:50 am

Hello Oscar

Can I operate a ESC with BLHeli with Oneshot125 protocol with a simple PWM? I want the options that BLHeli suit have but I will use a controller that doesn´t have Oneshot125 protocol. (Is not a racing drone)

Oscar 6th November 2018 - 12:58 pm

Yes of course.

Peter 14th May 2018 - 11:44 pm

Hi Oscar. If I am trying to get a quadcopter-like design to work along with 4 servos, should I then use PWM so that there are no timer conflicts on my F3 flight controller?

Sergio 13th April 2018 - 11:37 pm

Hello Oscar,
I’m curious if you may know what the control interface used in Hobbyking YEP 120A-HV ESC? I’ve purchased this controller from Hobbyking and it came without any documentation. The type of interface is also not mentioned in the description available for this controller. It is only noted that it has an optocoupler on its input. I woud greatly appreciate if you can share any information available on this unit.

Thanks and Regards,

Tyler 6th December 2017 - 6:32 am

How do I identify what protocol my esc are using? I’ve upgraded my FC to a Kiss. But I don’t know what protocol to use for the ESC mode.

Oscar 12th December 2017 - 1:49 pm

You can set the protocol in your FC software, so you should be able to tell from there.
As to what protocol your ESC can support, you have to look it up from the product specification.

Sange 13th August 2017 - 4:21 pm

I have a question that
I just updated my Kingkong 12Amp BlHeli ESCs to the latest 14.9 firmware.
Now will I be able to use the dshot or multishot or even oneshot42? Because I am using oneshot125 right now (I think, because I didn’t see much difference between oneshot enabled and disabled).

Stefan Wilkens 23rd July 2017 - 9:59 am

A new addition is showing up here, ProShot which sends hex data over three pulses with an added crc. The total package is shorter than dshot, longer pulses allow for caps to reduce noise.

Support is being built in to beta flight

Oscar 24th July 2017 - 9:38 pm

Thanks, yea we’ve just covered that in our latest blog post :)

Simon Kirby 12th July 2017 - 2:38 am

You can run SimonK at 64kHz if you’d like. Just change RCP_ALIAS_SHIFT such that it fits whatever timing you want. I tested it up to 256kHz PWM, and it worked.

Saijin_Naib 8th September 2017 - 5:50 pm

The SimonK? Nice to meet you, and thanks for your years of hard work!

If I may bother you, I’m wondering if there is any value in updating the firmware/bootloader on the 3DR Solo ESCs to your latest SimonK firmware build and enabling OneShot125 on them, possibly with active braking (unless that will cause more of an electrical issue on the Solo!) I don’t think it will fix the ground lift/bounce problem the ESCs have, but I’m just curious what your take is on it (if you have one). 3DR forked your firmware back in 2015 or so, so I know you’d made fixes/advances/changes since then, and from what I’m reading, the 3DR FC firmware has a slew rate limiter in place to prevent the ground bounce to some level. I’m not sure if faster/more accurate/synced signaling would prevent the signal from getting interrupted. (I’m also not knowledgeable enough in this material to fully understand, just pulling info together).

I’m planning on doing the flash as soon as I can figure out a harness to connect to the 3DR ESCs, but any advice/thoughts are always more than welcome!