Basic ESC r3 PWM output frequency

Hello Dear,

We just acquired the new Basic esc r3 and we want to change the frequency of the PWM output from 24 KHz to something lower or higher. My questions are:
1 - Is it possible to change it in the firmware ?
2 - If yes, how we can change it ?

The esc is using the BLHELI_S firmware.

Thank you

Hi Youssef,

Unfortunately, it is not possible to easily change the default PWM frequency of BLHeli_S. There are many settings you can easily change with BLHeliSuite, but unfortunately PWM frequency is not one of them. The good news is you should still be able to do this, but it will take some work. You will need to modify the firmware and compile your own own version with the desired PWM frequency, and flash it the ESCs.


Dear Adam,

Thank you for your reply,
I did the modifications on the firmware and I generated the HEX files.
But I don’t know which HEX file is corresponding to the MCU on the basic esc r3,
In this page there are some esc models with the corresponding HEX file, but the basic esc r3 is not among them,

Can you please help me to find the appropriate HEX file to flash,

Thank you

@revdevlev The firmware has a hardware abstraction layer based on (component connections to mcu (A-Z), high side or low side fets (H/L), and deadtime in nanoseconds. Our basic esc hardware is R_H_15.

Hi Jacob.

What does H/L mean? Does H mean you are using p-channel MOSFETs (active low) for the upper switches? and L means you are using n-channel MOSFETS (active high) for the upper switches?

Also, how do you actually get to change the deadtime? Do you just change the file name?

Really appreciate your thoughts.