I currently use a PIC's ECCP (Enhanced CCP) module to do my PWM switching on my H-bridge-based DC motor control. I use the method where i turn on a bottom fet, keep it on, and clock the top opposite FET.
I want to do "locked antiphase" clocking now, where the top left and bottom right FETs are pulsed simultaneously are always the complement of the top right and bottom right FETs, respectively, which also pulse simultaneously. Thus a 50% duty cycle stops the motor; >50% moves it clockwise;