Hello Frnds,

I am trying to drive 2 BLDC motors and a servo using an ATMEL SAM3x(it has 8 pwms). so, if my math is right i will need 6 pwms per BLDC , which makes it 12 PWMs just for 2 BLDCs.

I cannot change the controller. Can i use s/w PWMs via code ? Is that ok for such an application ?

Also, i have seen many hobby king ESC (elect speed controllers of BLDCs) having just 3 lines o/p and 1 i/p for PWM. How do they do that ?

Kind of split 1 PWM into 3 ?

mother controller(1 PWM) -> ESC->BLDC(U,V and W)


Kindly suggest pls.


Vinod.

 

Why do you need 6? I assume you are using H bridges and MOSFETs so you can just use static digital control on the low side and apply Pwm signal to the high side. 3 should be enough for each motor.

If you want to bit bang the PWM, that should work fine too. Just remember, the pins on your controller can only drive 20 to 30 mAmps, do not drive motors directly from your controller.

Here is an app not from Amtel on bldc motors.
http://www.atmel.com/Images/doc9143.pdf