how to use INTERRUPT?

[keithv]

ON INTERRUPT waits for the pause to complete before executing the interrupt routine. To get over this issue use short pauses in a loop. Here is a non interrupt option.

Thanks! That does solve my immediate problem, but I'm planning on doing more complex stuff with the "length" var. Ultimately, I want the LED to continue blinking uninterrupted while the button is being pressed. I'm doing it one piece at a time, but ultimately the blinking LED will be in sync with a PWM, and the button will be a tap tempo to control the frequency of the PWM. The DT Instant Interrupts looks to be exactly what I need for this project. It's got the button. It's got the LED. ANd it's got the timer.