BLHeli_32 ESC Firmware Overview

by Oscar

We have official BLHeli_32 confirmation from BLHeli Developers. Let’s find out what it is about, what advantages it brings, and what changes there are moving forward.


What is BLheli_32?

BLHeli is an ESC firmware, and BLHeli_32 is the 3rd generation after BLHeli and BLHeli_S.

BLHeli_32 is written for ESC‘s that utilize 32-bit MCU (STM32F0 Cortex-M0 at 48MHz), unlike BLHeli and BLHeli_S ESC’s that runs on 8-bit processors. BLHeli_32 does not work with 8bit Atmel or Silabs ESC’s.

Check out this article to learn about ESC firmware.

Benefits of BLHeli_32 Firmware on 32-bit ESC

The 32bit processor on BLHeli_32 ESC has faster clock speed than the 8bit processors in BLHeli_S ESC’s. But BLHeli_S has already set the bar high for performance, it would be interesting to see how much better BLHeli_32 is than BLHeli_S.

With the increased in processing power, faster input signals with lower latency and higher update rate would be possible in BLHeli_32, such as Dshot1200 or even faster protocols! (Read about DShot)

The most exciting news about the 32-bit platform is the possibility of future functionality and features that simply wasn’t possible on 8bit ESC’s, including

  • programmable PWM frequency of up to 48KHz
  • Auto-timing for higher efficiency and realiability
  • Current limiting (with built-in current sensor on ESC)
  • Adjustable “Brake on Stop” force
  • Improve direction change in Bidirectional mode
  • ESC Telemetry
  • Configuring from FC using DShot commands

48KHz PWM frequency and Auto motor timing have been reported to improve flight performance noticeably.

Note that these features are just ideas from the developer (aka sskaug) at the moment and haven’t all been implemented yet. Some of these sound familiar from the KISS 24A ESC’s. Anyway we should discover more about the new possibility as development continues.

BLHeli_32 Features and Tutorials

Changes From Previous Firmware

The previous BLHeli and BLHeli_S are open source, however the developers have decided to close source the new 32bit firmware. Their names might maintain the same prefix, but we were told BLHeli_32 has been created from scratch. (BLHeli and _S are both Assembly based while BLHeli_32 is C based) ESC manufacturers will have to pay BLHeli developers a licence fee directly to use their 32bit firmware, therefore expect some increase in ESC price.

When asked why the project has become close-source, sskaug replied:

From starting as a personal project to make my mCPX helicopter brushless, BLHeli as come a long way. Some of the major milestones were when we decided to pursue the multirotor segment as well, still as a hobby project, where people flashed various (non BLHeli) ESCs with BLHeli FW. Still moderate activity and efforts. But then at some point, probably starting with the Littlebee, manufacturers started making dedicated ESCs for BLHeli FW. Which I think was a major step forward for the community, as now we have a plethora of very good ESCs for multicopters. Then there was a new milestone where we decided to pursue BLHeli_S, as smoothness of BLHeli was still inferior to other ESCs in the market. And by this time we had close to 20 manufacturers doing BLHeli_S! Supporting which is actually a significant workload.

So then came the next milestone – what was next? ARM 32bit MCUs were a pretty obvious choice, as they are flooding the market from various manufacturers and are getting quite cheap. But at least for me, I was at a point where I did not want to undertake the workload I knew would come without some returns. So this is where we are now, closed source with a modest fee for some returns on the work we actually do. While still supporting many manufacturers and keeping the generally low cost profile of BLHeli.

Hopefully BLHeli_32 will also serve the community well, and bring ESC performance and the hobby as a whole even some more steps forward.

One thing remains the same is using BLHeliSuite for flashing and configuring ESC’s, which is known to be incompatible with Mac and Linux but only Windows. BLHeli Configurator Chrome App was created to tackle this issue by third party developer Andrey Mironov,. But we found out that it won’t support BLHeli_32 since it’s close-source.

Here is how to connect to BLHeliSuite32 via FC passthrough.

BLHeli_32 BLHeliSuite configurator for 32-bit ESC

BLHeliSuite will require an internet connection in order to flash/update firmware and configure settings, that probably means you can’t do it at the field easily. The serial number of the ESC has to be validated at the manufacturers, this is to prevent clones or illegal use of their firmware.

ESC’s that support BLHeli_32

Here is a full list of ESC’s for mini quad, you can look up which ones support BLHeli_32 firmware.

I compiled the specification of all ESC’s for mini quad in this spreadsheet so you can compare them more closely.

In order to run BLHeli_32 firmware, the ESC must be designed specifically for the firmware. That means 32bit ESC’s that already existed before the firmware was released might not work with BLHeli_32. Also note that some 32-bit ESC’s might only run their own factory firmware, so make sure you check before purchasing.

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Patrick 12th October 2021 - 3:39 am

I am currently getting a lot of stalling/dsync on startup with load applied. With no load no problems. I have pretty much tried everything in the settings. When I use a Simonk esc on the same motor the issue disappears.y next move is to add a cap but looking for some more suggestions.

Ahmed Ibrahim 27th August 2020 - 1:45 am

I’ m designing an ESC board sing STM32F501and I want it to be compatible with BLHELI32. How can I know which Pin of the Microcontroller should connect to the motor?

David Posea 5th February 2019 - 5:04 am

I know it’s an old thread, but I thought I’d offer some answers. I have 4 aria (dys) 40 amp esc’s. That is what they add and stickers on them say. However, the firmware is for 35 amp ESCs by aria, and so far I have not been ale to find any other firmware that is flashable. These same ESCs are rebranded to at least 6 names, wraith and hackrc and dys and several others. I can configure via passthru or with an arduino nano, and I’m sure the other methods work too. I haven’t had any issues with these so far, but they’ve been out over a year and there are no firmware updates that I am aware of. Wait, there may have beeen an update from 3.4 to 3.6, I downloaded the latest blheli suite tonight and 3.6 was the latest.

I also am on linux running via wine, just go into the ~/,wine/dosdevices directory and run ls -l to see the com port to /dev/tty* mapping. WHen I connect my Ardupilot it /dev/ttyACM0 and my nano is /dev/ttyUSB0. ttyUSB0 is linked to com33 by default and com33 works great in BLHeliSuite32.

Jaroslaw 13th January 2019 - 12:32 am

BLHeli32 Suite is working on Linux under Wine. I have followed this tutorial:, but I only needed /dev/ttyACM0 symlinked. I have Kakute F7 and pass-through is working flawlessly. I hope it helps someone :)
Thanks Oskar for this blog, good job! :)

Tim 23rd May 2018 - 8:52 am

The DALRC Engine 40A 4-in-1 ESC does not have ESC Telemetry according to the specs and reply from seller on Banggood page.

Marcin 12th March 2018 - 5:11 am

So blheli32 is paid for cutomers or not? If I get ESC32bit I can just flash blheli32 and this is free right? So where is this license? For manufacturers? When they want to release 32bit ESC they have to pay them? Can’t they sell it without firmware (without paying) and customer will just flash it by himself? Or it is not possible to flash only update?

Will 17th February 2018 - 12:47 am

Siskin_st thats what is on my esc and they get hot and twich mid throttle

KuzyaTron 5th December 2017 - 4:34 pm

One question I can’t seem to find answer for is what a higher PWM frequency does. Any insight? Thank you

Oscar 12th December 2017 - 1:48 pm

google, mini quad motor update rate

aaron 26th October 2017 - 10:47 pm

i have a macbook and can,t use blheli_32
really damn pain in the ass. paid full price for my esc x4 and can,t run blheli on my macbook not even via chrome!??!
are u guys gonna fix this soon??

thibault 13th October 2017 - 4:03 pm

why always 25A or 35A …never 30A, which is the best amp rate for most of us ???

Oscar 19th October 2017 - 3:38 pm

Depends on your motor and props amp draw.

Krotow 8th September 2017 - 7:44 pm

Paying one or two bucks more for ESC with quality firmware is not a great price. However I wish to remain the possibility to configure and flash 32-bit ESC’s from Linux too. So dear developers! If you wish to get your butter on bread, I have no objection about that. But please keep us from being forcefully locked in one particular OS in our computers. If you’re keeping new firmware closed then maybe create a public API to it. Or create your own BLHeli_32 configuration utility which works on Linux and Mac too.

Roger Bivins 9th July 2017 - 10:00 pm

1st and foremost, for what it’s worth, I need to thank you for your generous contribution of time and knowledge to this sport.
Without the support which you, Joshua and a handful of others so kindly provide, the technical aspect of this endeavor would surely prevent many like myself from any real progression whatsoever, thus ending, thru sheer frustration, any possible hope of enjoyment.
As a total noob, having only two simple builds worth of experience, I have made a serious error in selecting esc’s for my 3rd project, a 3″, iflight frame, with 1407-3500kv motors and these esc’s
iPeaka Mini25A 32bit BLHeli_32 ESC OPTO (2-4s) DSHOT1200 Compatible

I have made every effort to use as high quality components as I could reasonably afford when building and these esc’s and motors were purchased as a package.
My thinking being, I’ve read much praise of the BlHelis-32’s and surely being sold as a package, the motors would be as near optimal pairing as anything I could hope to guess at buying individually.
Having completed the build, using an HGLTECH AIO F3 V4 FC, and a new Runcam Eagle 4:3, I find myself lost trying to set up thru Betaflight.
I understood going in that Dshot 1200 is not currently supported via the latest stable BF version, but had hoped I could run Dshot 600 or ?, until the stable version of BF DS 1200 came out, as I am not nearly a skilled enough pilot to appreciate the difference nor confident enough in flashing software unnecessarily.
I have used Blheli BF passthrough once to flash-the Littlebee esc’s on a previous build, but had hoped to just sync these thru BF & use whichever version BlH they were shipped with.
Now, considering the investment sunk into this quad, I fear loosing all the smoke on startup.
I have built a light bulb smokestopper and verified that at least I havnt reversed any polarity, I think.
I am sorry for this rediculously long message, and for imposing your time, but, I have found no local source of information and after hours of YouTube and reading posts until my eyes have blurred, I would be most grateful for any words or guidance you may be willing to give me toward finishing this last part of set up.
Thank you.

Philip Dezsö 13th July 2017 - 5:00 pm

I’ve never posted a comment nor reply here but do want to help you out as you seem like a good guy messing around with very new stuff almost nobody has experience with yet ( talking about the 32bit esc here ). We can continue the chat here or you throw me an email to [email protected] and I wil help you from there on. Sounds like a plan?

Wait to hear from you.

Mateusz 20th May 2017 - 7:35 am

Going commercial is the moment when greed wins. Every project is an effort, but some people are willing to resign from own benefits and the net value of that is always an advancing product which everyone can improve. Imagine flight-software being commercial. Anyway, BL_Heli32 is NOT the first attempt to bring 32 esc software into market, not only KISS32 tried that but there were ESCs with arm mcu’s long before blheli_s existed. They all never reached such interest as blheli_s, but they all also have common factors either price or closed source. Having said that, making software for ESC on stm32f0 is not that difficult compared to assembly. So that’s why serial key will be needed to prevent open-source competition from implementing trivially simple software so BLHeli can get money for not so new thing ?

boli 23rd May 2017 - 7:56 pm

The guy have been devoting his time to provite quality software for the community, and drone racing wouldn’t be there without him.

People have to eat, pay their bills, heck, become milionnaire. I don’t care. He worked years for that, so if today he wants to cash out, good for him.

When SimonK was charging a licensing fee back in the day for less than reliable software, it wasn’t that much drama …

Felix 17th May 2017 - 9:24 pm

How can I flash thoose, I’ve heard they won’t support flashing over Fc from the beginning?
Well not flashing but more configuring.
Will I have to buy an Arduino or will a Ftdi or hos they’re called adapter work?

Oscar 18th May 2017 - 12:53 pm

I am not sure yet I haven’t received my BLHeli_32 bit ESC and tested them.
But I assume it should be the same as BLHeli_S in terms of flashing and configuring… only difference is you will have to have internet connection for it to work.

LoWLoW82 20th May 2017 - 9:08 pm

do you have any news about the way to flash this esc because i cant do it through my betaflightF3 FC…

heath 8th July 2017 - 6:09 pm

need latest bf 3.2

Philip Dezsö 13th July 2017 - 5:03 pm

No you can’t, you need the not yet publicly released BF 3.2.0 hex for your FC. There are Beta builds to try but are constantly updated.

Jessie Kenney 16th April 2017 - 5:27 pm

Ok, I’m new to the hobby. So are these better than the D-Shot esc’s?

Oscar 26th April 2017 - 8:46 pm

DShot is not a type of esc, it’s a protocol.
BLHeli_32 will also support DShot.

Hay beseret 13th April 2017 - 1:12 pm

Could anyone find form factor details (size/weight) on theses ?

Oscar 14th April 2017 - 6:14 pm

check FPVModel’s preorder page (link in article)

Flytohigh 11th April 2017 - 11:44 am

I’ve heard that Maytech also is working with these blheli32 ESCs right now.