How to read analog signals?

[LinkMTech]

Here's something untested you can try. Two methods of rapid fire but you also need to add a 330 Ohm resistor between the button and the input so the PIC can sense a press then drive the same pin as an output even if you keep holding the button low.
I used the names pulse_fire and rapid_fire just to make them seperate.
If it does work for you, adjust the PAUSE times to suit your needs.

' This one fires off 5 shots per press or continueously if button held
pulse_fire:                 
    i=0                     ' Reset increment counter
    TRISIO = %00000001      ' Port 0 input, rest outputs
    while GPIO.0=1: Wend    ' Wait here until button pressed
    TRISIO = %00000000      ' Port 0 now an output
        for i=1 to 5        ' Set number of rapid fires per button press
            low GPIO.0      ' Hold output LOW
            pause 50        ' Held LOW for 50ms
            high GPIO.0     ' Turn OFF output
            pause 50        ' Keep OFF for 50 ms
        next i              ' 
goto pulse_fire             ' Go back, continue if button still pressed or 
                            ' wait until pressed again.
                            
' This one just continueously fires as long as button is pushed
rapid_fire:
    TRISIO = %00000001      ' Port 0 input, rest outputs
    while GPIO.0=1: Wend    ' Wait here until button pressed
    TRISIO = %00000000      ' Port 0 now an output
            low GPIO.0      ' Hold output LOW
            pause 50        ' Held LOW for 50ms
            high GPIO.0     ' Turn OFF output                                     
            pause 50        ' Keep OFF for 50 ms
goto rapid_fire             ' Go back, continue as long as button pressed

Here's the schematic to the resistor add on: