PIC Microchip Half Bridge PWM

half bridge pwm

I am using PIC16F883 for my Push pull Inverter project
I am using PWM module configured for Half bridge

my inverter frequency is 50 Hz. fixed ( Period 20 mSec. )
so I set system frequency to 500 KHz internal oscillator any higher value is not possible

1) for Half bridge PWM Period should be 20 mSec.( 50 Hz ) OR it should be
10 mSec ?

If it is 20 mSec. what will be duty cycle ? There will be 2 ON pulsec in one
period

In datasheet page 135 figure 11.8 shows different ON time
for 2 O/Ps P1a & P1b

Push pull Inverter with different On time of two MOSFETs is absolutely NO.

2) I want to start/stop my push pull inverter

a) I want stop PWM instantly ,terminate current cycle in between
can I use TRIS register ? This will be used in case of Overload.

b) I want to stop PWM in systematic way means finish current cycle & then
stop for this can
I use ECCPAS bit ? set/clr through software .