Exciting news for the FPV community: Flight controllers and ESC are about to get a lot cheaper thanks to the introduction of AT32 MCU in these boards! SMT32 flight controllers and flight stacks have become more expensive in recent years, with a complete flight stack costing over $100 became a norm. However things might change in the near future thanks to a new player entering the market – Artery AT32 chips! For example the latest NeutronRC F435 45A AIO, featuring a AT32 MCU, priced just at $47. The price difference is substantial, demonstrating potential considerable savings for FPV drone pilots. However, there are factors you might want to consider before jumping in.
The Problem with STM32
The micro controller unit (MCU) is the brain of our flight controllers, and the STM32 MCUs have long been the industry standard ever since the beginning of 32-bit FC, offering stability and performance that others couldn’t match. If you are not familiar with MCU in flight controller, check out this tutorial: https://oscarliang.com/f1-f3-f4-flight-controller/
However, the global silicon shortage and inflation in recently years have led to a significant increase in chip prices. This has prompted manufacturers to search for viable alternatives to maintain competitive pricing for FC and ESC. As a result, manufacturers have been leveraging lower-end parts such as the STM32 F4 series to manufacture more affordable components. A perfect example of this strategy is the Speedybee F405 V3, which, in 2023, stands out as a highly popular FC/ESC stack, primarily owing to its cost-effectiveness.
Recognizing this trend and to further address the STM32 cost challenge, companies are now exploring an entirely different, yet highly economical MCU option – the AT32.
What is AT32?
The AT32 is a MCU made by ArteryTek. It’s important to note that the AT32 is not a clone or a direct drop-in replacement for the STM32. To work with Betaflight, the AT32 will require some adaptations. However, considering its comparable performance and cost-effectiveness, it presents itself as a viable alternative to the STM32 MCU for our flight controllers.
Thanks to the comparable functionality and performance, you won’t be losing any advanced features or computational power when switching from STM32 to AT32. The truly compelling aspect of AT32 microcontrollers is their affordability compared to STM32.
In fact, AT32 MCU (AT32F421) are already being used in some of the latest ESCs, including the Hobbywing G2 45A, 65A 4in1 ESC, which we recently reviewed. It runs BLHeli_32 firmware, but you will also find this chip that on AM32 ESC.
Below is a overview of the specifications of popular STM32 F4 chips used in flight controllers and the AT32F435.
|MCU||Package Size||Processing Speed||Flash Memory||SRAM|
The new chip we’re starting to see in flight controllers is the AT32 F435. This chip offers performance between STM32’s F405 and F722, running at 288 MHz, compared to the F405’s 168 MHz and F722’s 216 MHz. Despite being based on the same M4 core CPU as the STM32 F4 series, it offers performance comparable to the larger M7 core found in the F7 series, thanks to increased clock speed and RAM. Additionally, with its smaller package size, the AT32F435 also emerges as a superior alternative to the STM32F411 for tiny micro quads.
What makes the Artery chipset really stand out is its price-performance ratio. The AT32 F435 is cheaper than STM32 F4 counterparts, which leads to the lower cost of flight controllers.
Where Can You Purchase?
We can anticipate more manufacturers offering controllers with the AT32 chipset. It brings substantial benefits to the end-user, particularly in terms of cost.
If you’re intrigued by the potential of AT32 flight controllers and want to give them a try, they are available for purchase now. Currently, NeutronRC appears to be the only manufacturer offering them.
One of the first AT32 flight controllers is an AIO board featuring a 25.5×25.5mm mounting pattern, powered by an AT32F435 MCU. It comes with an integrated 4-in-1 ESC that operates on AM32 firmware, powered by an AT32F421 MCU. There are 3 versions differentiated by ESC ratings of 35A, 45A, and 55A. The 35A version is available at an astounding price of just US$39.5! There’s also a slightly more expensive BLHeli_32 version. Get yours here (not affiliated): https://www.aliexpress.com/item/1005005551828962.html
For those seeking an alternative, there is a different FC design that uses a larger variant of the AT32F435 chip. This is a stack with separate FC and ESC boards, featuring a 20x20mm mounting pattern with removable 30x30mm extension mounting tabs. This FC features 5 UART ports and come equipped with a BMI270 gyro. Find it here: https://s.click.aliexpress.com/e/_DcgHxt7
Update: thanks to comments, we found another affordable FC that uses AT32 chip. It appears to be using AT32F435VMT7 and compatible with ATBetaflight. Find it here: https://s.click.aliexpress.com/e/_Dk6ia0z
Caution: Compatibility with Betaflight
At the time of this article, AT32 flight controllers are not compatible with Betaflight yet. The NeutronRC F435 flight controllers for example, are running a special fork of the old Betaflight 4.3, called ATBetaflight.
ATBetaflight’s GitHub page can be found here: https://github.com/flightng/atbetaflight
If you want the latest and greatest features of Betaflight, it might be wise to hold off for now. That being said, work is actively underway to extend Betaflight support to these new AT32 flight controllers and is expected to arrive in Betaflight 4.5. There’s no exact date yet, but we’re certainly looking forward to trying out these more affordable flight controllers.
Although it may be premature to hail the AT32 as the new revolution in FPV drone technology, it’s undeniably a thrilling advancement. The Artery AT32 chip promises to deliver powerful, reliable performance at a significantly lower cost, making the joy of FPV flight more accessible.
Very nice Oscar!
I just found this FC.
I think it also has the same chip.
STM32H562VGT6 is better than china-clone AT MCUs and doesn’t have the same project overheads that introducing AT32 support has.
IMHO it would have been better to add support for Risc-V / ESP32 / or start off-loading some computational tasks to a cheap FPGA co-processor which are stupid-cheap these days (Lattice ICE40 series, for example).
If there was anyone to listen to about this topic it’d be this guy. I would gladly help fund a GoFundMe so Dominic could learn Mandarin and go to China to visit every manufacturer and tell them how to make much better products at lower prices.
PS love my h7rf thanks Dominic
And it is 20x more expensive. F… STM.
Great article as always Oscar! A gentleman posted this article on iNav group which discusses interesting comparison between the two platforms
It’s not an ATMega chip, I’m afraid.
Thanks I love your on the spot about new teck
Keep them coming!!
Looks like it might eventually be ardupilot compatible too with its flash memory and sram amount.
Interesting, when they will be officially supported by BF days of STM hegemony in FC world will be over :)
but for now i would advice caution, they maybe some “small” things that will make them not great candidate for a brain of an FC, let’s BF devs does they jobs. For example GD32 cpu family is on the market for very long time, they are 99% STM compatible and 40% cheaper but there is no BF version so fare.
Take into caution that AT32 is better than STM32. The MIPS of the chip make it better than a F405, but not better than a F722, for example. The MHz are not the only way of measuring it.