I really appreciate your help, I hope you are not tired of my dumb questions!
I tried your program; the clock starts when power is applied but nothing happens when footsw is low. When footsw goes high, the clock stops and reset will not start it. I have to turn power off and on or if I put footsw low, the clock will start again, as long as footsw is low. I put the nap statement in to see if it was seeing that part of the program; it isn't.

I don't understand the WHILE - WEND, what is that doing?

TRISB = %00111111 'PORT B ALL INPUT, EXCEPT 6 & 7 OUTPUT
option_REG = %01111111 'enable weak pullups on port B
FOOTSW var portb.5 'Foot switch OR CCREADY must be high
READY var portb.4 'at start

T var word
J VAR WORD


RENCA var portb.7 'FREQUENCY OUTPUT TO J1 PIN 13
EJECT var portb.6 '100 mS PULSE TO J1 PIN 21
on interrupt goto poo
START:
LOW RENCA : LOW EJECT

WHILE READY = 0
WEND
GOTO START
DISABLE INTERRUPT
poo:
IF NOT FOOTSW THEN FALSE
nap 6
T = 100

freq:

toggle renca 'frequency should be 500 Hz (2mS period)
PAUSEus T*7 ' 1 mS at 4 mHz

GOTO freq
false:
RESUME
ENABLE INTERRUPT

end