Hi,
You can use the eTPU set3 (motor control library) for that purpose. See AN2958 for basic info; http://cache.freescale.com/files/32bit/doc/app_note/AN2958.pdf.
Each precompiled eTPU function can be also downloaded from the eTPU selector, see following link: http://www.freescale.com/webapp/etpu/
I am not aware of any eTPU demos for driving BLDC on MPC5643M, but there are several demos for the MPC55xx family (MPC5554) using the eTPU to control motor. You can refer to those.
For BLDC motors search for AN3005, AN3006, AN3007 on the web.
Regards,
Petr
