So simple but it don't work

[malc-c]

Guys, I've been pulling my hair out all afternoon to get this working. All I'm trying to do is read a pin, if its low then goto one section. That section then contains the same line to check if the same pin is low and if so jump back to main.

Here's the complete code

;*************** Set up LCD *****************

DEFINE LCD_DREG PORTC                           ' LCD data port 
DEFINE LCD_DBIT 0                               ' LCD data starting bit 0 or 4 
DEFINE LCD_RSREG PORTC                          ' LCD register select port 
DEFINE LCD_RSBIT 4                              ' LCD register select bit 
DEFINE LCD_EREG PORTC                           ' LCD enable port 
DEFINE LCD_EBIT 5                               ' LCD enable bit 
DEFINE LCD_BITS 4                               ' LCD bus size 4 or 8 
DEFINE LCD_LINES 2                              ' Number lines on LCD 
DEFINE LCD_COMMANDUS 2000                       ' Command delay time in us 
DEFINE LCD_DATAUS 50                            ' Data delay time in us

;************* set up pattern data **********
    
Patt1 DATA 16,1,2,4,8,16,32,64,128,128,64,32,16,8,4,2,1 
Patt2 DATA 8,129,66,36,24,24,36,66,129 
Patt3 DATA 16,1,3,2,6,4,12,8,24,16,48,32,96,64,192,128,0 
Patt4 DATA 16,1,128,2,64,4,32,8,16,8,32,4,64,2,128,1,0 
Patt5 DATA 12,24,60,126,255,231,195,129,0,129,195,231,255 
Patt6 DATA 13,1,2,4,8,17,34,68,136,16,32,64,128,0 
Patt7 DATA 8,128,64,32,16,8,4,2,1

;************* set up PIC ********************

ADCON1=$07                                      ' PORTA all disgital
CMCON = 7                                       ' Digital inputs
CCP1CON = 0                                     ' PWM off
TRISA=%11111111                                 ' set PORTA as all input 
TRISB=%00000000                                 ' set PORTB as all output
TRISC=%00000000                                 ' set PORTC as all output
PORTB=0

audio var PORTA.0                               ;input from beat filter (+5v)
option var PORTA.2                              ;music or chase option select
sequence var PORTA.3                            ;pattern selection

;************* set up variables ***************

Patt    var byte [8]                            ;used to store the sequences
Patt[1]=Patt1
Patt[2]=Patt2
Patt[3]=Patt3
Patt[4]=Patt4
Patt[5]=Patt5
Patt[6]=Patt6
Patt[7]=Patt7

C var byte                                      ;used to advance through pattern
D var byte                                      ;used for the speed the sequence runs at
scale var byte                                  ;used in the POT command
Scale = 254                                     ;used to provide ragge with pot command
steps var byte                                  ;used for storing the number of steps in a sequence
swcount var byte                                ;used to select the required sequence required
swcount=4                                       ;set default sequence at start
sel var byte                                    ;used to select music or chase
sel=0                                           ;used to select mode 

;**************** main program ********************
main:

Pot PORTA.4,scale,D                             ;used to read value from 10k pot and set the speed

if sequence=0 then swcount=swcount+1            ;check to see if up button pressed, if so add 1 to SWcount
pause 60                                        ;debounce delay
If swcount>7 then swcount=1                     ;error trap for exceeding max patterns                      

if swcount=1 then LCDOUT $FE, 1, "Pattern 1"    'Clear display and show sequence number
if swcount=2 then LCDOUT $FE, 1, "Pattern 2"
if swcount=3 then LCDOUT $FE, 1, "Pattern 3"
if swcount=4 then LCDOUT $FE, 1, "Pattern 4"
if swcount=5 then LCDOUT $FE, 1, "Pattern 5"
if swcount=6 then LCDOUT $FE, 1, "Pattern 6"
if swcount=7 then LCDOUT $FE, 1, "Pattern 7"
LCDOUT $FE,$C0, "Chase Speed " ,#D	             'Jump to second line and show speed


if PORTA.2=0 then goto music
pause 60

read patt[swcount],steps                        ;read the first value of the selected patter and place it in the variable steps
for C = 1 to steps                              ;for / next loop
READ PATT[SWCOUNT]+ C,PORTB                     ;reads the step value for selected pattern and send it to PORTB 
PAUSE D                                         ;delay for speed
NEXT                                            ;advance through pattern
goto main:                                      ;go to start of main program

music:

if PORTA.2 = 0 then goto main                   ;if A2 is low then goto main
pause 60                                        ;debounce delay

LCDOUT $FE,$C0, "Music Selected " 	            ;show that music has been selecterd

read patt[swcount],steps                        ;read the first value of the selected patter and place it in the variable steps
READ PATT[SWCOUNT]+ C,PORTB                     ;reads the step value for selected pattern and send it to PORTB 
If audio=1 then C=C+1                           ;if pin is high a beat is present, so advance pattern
If C=steps then C=1                             ;check to see if end of the patetrn is reached
goto music:                                     ;go back to music and start again

I've tried

branch sel,[music,main]

I've also tried

if option=0 then sel = sel + 1
if sel = 1 then goto music
if sel = 2 then goto main
if sel>2 then sel =0

But no mater what I try the program won't jump to the music section. If I press and hold the button down (thus grounding the pin) the program seems to halt at the end of what ever pattern is selected, and the LCD displays rapid values for the speed.

The hardware checks out and PORTA.2 is indeed being pulled low when the button is pressed (10k pull up holds it at +5v).

I'm sure its something really obvious that I've overlooked.. but at the moment I just can't see why it shouldn't jump to each section when the button is pressed...

[BigWumpus]

at the beginning of the "music:"-section, porta.2 is checking for zero, so the program jumps immediate to "main:", if it ever reaches "music:".