In the past month it has come to light that at least two FC's have appeared on the market with an ArteryTek AT32F435 MCU rather than an STMicoelectronics STM32 MCU. The advantage of these is that they are way cheaper than STM32 MCU's. The downside is that Betaflight doesn't currently support non-STM32 MCU's, so to use flight controllers with an ArteryTek MCU it requires flashing a fork of Betaflight called ATbetaflight which can be found at the link below...

https://github.com/flightng/atbetaflight

Steve Evans (an official Betaflight developer) has posted a comment in the Betaflight User Group on Facebook stating that official Betaflight support for the ArteryTek MCUs is already being developed in the master branch and will be available in Betaflight 4.5 onwards which will then negate the need to use the forked ATbetaflight versions.

There are a few related posts on Facebook below for anyone interested:

• NeutronRC -> https://www.facebook.com/100063693905277...8462209393
  
• FPV Life -> https://www.facebook.com/groups/FPVLIFE/...9168304608
  
• FPVCycle -> https://www.facebook.com/groups/37915594...0908384849
  
• Betaflight User Group -> https://www.facebook.com/groups/betaflig...9842537759
  

NeutronRC seems to be the only manufacturer currently producing FC's with an ArteryTek AT32F435 MCU but if they prove to be reliable then other manufacturers could well follow suit meaning that we might be back to sub ~$50 USD priced FC's just like in 2019. The NeutronRC FC's currently only seem to available on AliExpress but if they become popular and reliable then I'm sure we will start to see other mainstream FPV stores stocking them. See the AliExpress links below...

• https://www.aliexpress.com/item/1005005187225963.html
  
• https://www.aliexpress.com/item/1005005551828962.html
  

It turns out that Pawel Spychalski actually noticed these back in January this year (HERE) but I've not seen anything publicised about them on social media until just recently.

That’s potentially exciting for a cheap bastard like me.

Datasheet for that mcu:
https://www.arterychip.com/download/DS/D....02-EN.pdf

I'm actually writing a post about this new chip I'm quite excited about these because they are actually a lot cheaper. They are available to buy now but only supports BF4.3 (a forked version), so i'd probably wait until BF4.5 to try these (will be supported by Betaflight officially then). Meanwhile I think they will probably improve their hardware and designs.
Edit, here's the post i said i was working on: https://oscarliang.com/at32-flight-controllers/

I’m looking forward to that post.

I want to say holy shit (and will do).

https://www.aliexpress.com/item/1005005551828962.html

AT435AIO AM32 55A for £50
AT435AIO AM32 35A for £36

If the ESC is reliable, that will be a game changer. So tempted to order one. Need to see if the Quicksilver guys will port it as well. But that 55A one would run pretty much any motor you would/could want.

Yeah. The 35A aio for $39 looks like it would meet all of my typical needs. Hell, it even has a barometer and blackbox.

Yeah blackbox for that sort of money. It uses BMI270 gyro as well. I could see me buying a couple of the 35A for a start. That would square away two future projects for around the price of a single Speedybee stack.

(20-May-2023, 10:01 PM)Pathfinder075 Wrote: https://www.aliexpress.com/item/1005005551828962.html

AT435AIO AM32 55A for £50
AT435AIO AM32 35A for £36

If the ESC is reliable, that will be a game changer.  So tempted to order one.  Need to see if the Quicksilver guys will port it as well.  But that 55A one would run pretty much any motor you would/could want.

Don't forget the delivery charge and dreaded 20% VAT for UK buyers (added automatically at checkout) which brings them closer to £45 and £60 respectively, but still cheaper than any STM32 alternatives. Maybe some UK vendors might eventually start stocking some. We can only hope.

YourFPV probably will. The guy who runs it, Gaf, tends to stock things that Unmanned and HobbyRC don't/won't. He had some AtomRC F411 and F405 FC's in a while back at £20 and £25 respectively. I got the last F411. You just have to keep your eye open. Also CNHL Lipos that you can't get from CNHL, which for me are the 3S 550mAh ones. Can't get them from CNHL, but he sells them and they are competitive in price.

You know the VAT thing is a misnomer. I've put several orders into China in the last year and not seen any sort of import charges, VAT, etc. It could be the companies are registered for VAT over here, but i'm not 100% sure of that, the invoices don't show anything. The amount I mentioned included the postage, which comes up as £2.39 on SpeedPAK (for me). Seems all companies use that courier. I've had orders from Ali, JMT, Xinte amongst others and all use SpeedPAK and all seem to be about the same price. Go figure.

So I just added to cart and hit checkout and it still says £35.65. :/ I know it's not adding on VAT for some reason, just don't know why. But even with VAT and postage it's still not much more than £42 for the 35A version. I paid £35 for a 12A AIO the other week. If £7 more gets you a 35A, I can live with that.

(20-May-2023, 11:14 PM)Pathfinder075 Wrote: So I just added to cart and hit checkout and it still says £35.65. :/  I know it's not adding on VAT for some reason, just don't know why.  But even with VAT and postage it's still not much more than £42 for the 35A version.  I paid £35 for a 12A AIO the other week.  If £7 more gets you a 35A, I can live with that.

That's odd. I order stuff from AliExpress quite frequently and since the new overseas EU/UK VAT rules came into play a couple of years ago AliExpress always adds VAT at checkout for anything that totals less than £135 with shipping. I only ever got away without paying any VAT or import tax on a couple of items that were over £135. Everything else I had no choice as the VAT was just added at the checkout. Using a VPN via another country makes no difference and neither does setting the "Ship To" country as something different. As soon as you add a UK delivery address to the order VAT is then automatically added. It is AliExpress who charge and collect the VAT, not the individual vendor. I've never ordered from JMT or Xinte so I don't know if those vendors automatically add VAT at the checkout or not.

Yeah it's odd.

FTR, I do VPN in, but use a UK exit point when shopping and switch it all off for payments. The only time the VPN has made it cheaper was when buying games from certain online sites. If you used a US exit point they just went through and actually a couple of other sites that do hosting services were the same. But not for physical goods.

But I know there's a rule that says if the item value is under £30 you don't get charged import tax. i read it somewhere on the HMRC site. A lot of the frames I order rarely come to £30 including postage.

Don't know. TBH, if I can get an FC for £43, I'm not going to complain. If they want to send it to me for £36, I will be really happy.

It seems the board is running the open source AM32 ESC firmware and what is a 3in1 ESC driver?

Quote:11. ESCMCU:AT32F421 120MHz (AM32 Firmware)
12. FD6288 3in1 driver

I’m guessing they meant “3 phase bridge driver”.
Gate driver for the mosfets.
FD6288:
https://static.qingshow.net/fortiortech/...029372.pdf

I really want to get my hands on one of these aio’s.

It seems like a normal gate driver, I guess 3-in-1 just means it drives 3 sets of mosfets. This will be an interesting AIO to try, I see NeutronRC also have an inexpensive 1S ELRS whoop board (STM F4) and they also make the Flowshutter gyrologger for using with Gyroflow.

(21-May-2023, 11:47 PM)mstc Wrote: It seems the board is running the open source AM32 ESC firmware and what is a 3in1 ESC driver?

those AT32 f4 MCU is capable of running both Am32 and BLHeli32 firmware.
One of the latest ESC that uses AT32 F4 chips is the Hobbywing G2 4in1 ESC and they run BLHeli_32.