For w = 1 to 160
SOUND PortB.1,[110,1]

in here look to see if the flag is set that
we went through an interrupt.

Next w

But that sounds terrible!
simple thought here... if your PIC have an internal PWM module... why not using it as output? or an loop to trigger an external 555 reset pin with a specific PIC pin??? 555 as pulse generator...