Lpc2000

Hi all-

I am working on some motor control 'stuff' using the PWM and the A/D. 
I have configured the PWM to be single edge controlled with a 25KHz 
frequency. I would like to trigger an A/D reading slightly before the 
falling edge of the pulse. Is there any thoughts on how to configure 
the LPC2138 to generate an interrupt to take an A/D reading slightly 
before the falling edge of the pulse?

Thanks-
Tim