BLHeli ESCs can't be read?

I’m building a 450 drone using the BLHeli 20a ESCs sold on unmanned tech, however I can’t get them to be read by BLHeli suite using Cleanflight on my Naze32, an Arduino Uno or the BLHeli programmer also sold on the unmanned shop: the program just throws up the error “can’t connect to ESC, check power and connections”. Everything should work; the ESCs are powered by the battery, Cleanflight isn’t open so nothing’s interfering with the COM port and the ESCs are functioning normally, powering the motors through both Cleanflight and the transmitter. Although, 1 of the ESCs doesn’t seem to be functioning at all (the motor works fine) but I can’t see how that affects the other ones; I guess I’ll have to buy another one.

What’s going on? Any help appreciated.

Could you please let me know which exact ESC and USB linker you are using so I can try to help. One thing is that you must make sure you are using the correct SI or Atmel settings depending on what chip the ESC has on them. Also you will need to make sure your ESC’s are powered via a battery when connecting as the USB device does not provide any power.

I’m using these ESCs (labelled as EMAX I think) and the this USB linker, stated on the site as suitable for any BLHeli ESC. As I stated in the original post, I have been using my battery for power so that shouldn’t be an issue. From looking at the page for the ESCs, I can only gather that they use SI settings but even trying both SI and Atmel in different instances gave no results; even using an Arduino to try as if it had a SimonK bootloader instead of BLHeli still produced no results.


Do you remember when you purchased your ESC as I know that older firmware blheli firmware cannot connect via servo lead. Also emax ESC use silabs MCU so that USB linker will work with them, but firmware version is the problem I think.

Thanks for the response. I bought the ESCs about a month ago so I’m not sure if that’s recent enough, but either way, what should I do about the issue? Is there a way to flash the newer firmware without the servo lead? And if that’s not the problem, is it possible they are just faulty ESCs?

The only way to update firmware on these it to open them up and connect directly to 3/4 pads on the actual MCU. If you want to attempt this just let me know and I can send you some links (I’m on my phone right now). However by the sounds of it yourbesc are all working fine except for one of them.

With the suspect ESC are you able to connect it directly with a servo tester/ESC and double check the soldering to see if that is the cause of it not working?

The first thing I did after reading this was check the solder joints by eye and noticed it looked slightly wrong so I re-did it and the ESC works alright now; can’t believe I didn’t think of that before.

Although everything works mostly as expected now, I still can’t program any of the ESCs but if nothing’s broken, I don’t want to fiddle around with something unnecessarily like the MCU. Presumably I’ll be ok with everything now? It’s just a case of calibrating everything presumably.

:slight_smile: at least that was the problem, and yeah by default the ESC should work really well, jusylt calibrate them and you are good to go :thumbsup: