RE: [CAD_CAM_EDM_DRO] brushless servos without hall commutation

Provided that your encoder had an index pulse startup would be fairly
trivial. Send low speed PWM 3 phase to the motor which will rotate it
whatever the current position is and wait for the index pulse.

If you set the quad encoder high limit to 1/3rd or 1/4 of the actual
encoder
Resolution the pic will send an interrupt at each 1/3rd or 1/4 rev which
you can have a trivial ISR recognise as the commutation point.

Chris

>Interesting appnote.
>
>Unfortunately, all of the examples require hall sensors for
>commutation. There is a short section on using an encoder for speed
>measurement, but not for motor position sensing (and especially not for

>unknown startup states, which they don't really go into at all)
>
>Still a cool chip though.