And I set that in the registers, right? And then I can run a wire from PIN 17 to an interrupt pin and do an ON INTERRUPT command? Would it look something like this or totally different? I am going to try and find some examples.

horizloop:
ON INTERRUPT
PORTB.2 = 0
PORTB.3 = 1
PAUSEUS 139
PORTB.3 = 0
PORTB.2 = 1
PAUSEUS 50
ADCIN 0, adval ' A/D 8 bit value from PORTA.0 into adval
SEROUT2 PORTC.6,16416,[BIN8 adval,13,10] ' Output 8 bit word serially to PC from C.6
PAUSE 87
horizpulse = horizpulse + 1
IF horizpulse < 784