using same pin for multiple purposes

ADCON1 = 000111
TRISA = %111111
TRISB = %00000000
TRISC = %00000000
PORTC = %00000000
PORTB = %00000000
PORTA = %0000000
'***********************************************
#CONFIG
__CONFIG _XT_OSC & _WDT_OFF & _PWRTE_OFF & _BODEN_OFF
#ENDCONFIG
'***********************************************
Symbol PBUP = PORTA.0
SYMBOL PBDN = PORTA.1
symbol MCB = PORTA.2
SYMBOL S1 = PORTA.3
'***************************
SEQ VAR BYTE
LED1 VAR PORTC.0
LED2 VAR PORTC.1
LED3 VAR PORTC.2
LED4 VAR PORTC.3
LED5 VAR PORTC.4
LED6 VAR PORTC.5
LED7 VAR PORTC.6
LED8 VAR PORTC.7
b1 var byte
'********************
SEQ = 0
'CMCON = 7
'ADCON1 = %0
'***************************************




' MCB=1
'LOOP4:
' WHILE(mcb!=0)
' PBUP=0
' PBDN=0
' WEND

'AGAIN:
'IF MCB=0 THEN PORTA=0 : PORTB=0: PORTC=0
'IF MCB=1 THEN PORTA=1 : PORTB=1 : PORTC=1


'GOTO MAINLOOP
'GOTO LOOP4

FOR MCB=0 TO 1 STEP 1
PORTB=0
PORTC=0
MCB=MCB-1
NEXT

FOR MCB= 1 TO 0 STEP -1
PORTB=1
PORTC=1
MCB=MCB+1
NEXT





MAINLOOP:

IF PBUP = 0 THEN GOSUB UPP
IF PBDN = 0 THEN GOSUB DNN
PAUSE 200
GOSUB ACTIONS
GOTO MAINLOOP

'**************************
UPP:
IF SEQ = 9 THEN RRT
SEQ = SEQ + 1
PAUSE 10
GOTO RRT
DNN:
IF SEQ = 0 THEN RRT
SEQ = SEQ -1
PAUSE 20
RRT : RETURN

'****************************************
ACTIONS:
IF seq =0 THEN
LED1=0:LED2=0:LED3=0:LED4=0:LED5=0:LED6=0:LED7=0
PORTB=%01111110
ENDIF


IF SEQ = 1 THEN
LED1 = 1 : LED2 = 0 : LED3 = 0 : LED4 = 0 : LED5 = 0 : LED6 = 0 :
LED7 = 0
PORTB=%00001100
ENDIF


IF SEQ = 2 THEN
LED1 =0 : LED2 = 1 : LED3 = 0 : LED4 = 0 : LED5 = 0 : LED6 = 0 :
LED7 = 0
PORTB=%10110110
ENDIF

IF SEQ = 3 THEN
LED1 = 0 : LED2 = 0 : LED3 = 1 : LED4 = 0 : LED5 = 0 : LED6 = 0 :
LED7 = 0
PORTB=%10011111
ENDIF


IF SEQ = 4 THEN
LED1 = 0 :LED2 = 0 :LED3 = 0 :LED4 = 1 :LED5 = 0 :LED6 = 0 :
LED7 = 0
PORTB=%11001100
ENDIF


IF SEQ = 5 THEN
LED1 = 0 :LED2 = 0 :LED3 = 0 :LED4 = 0 :LED5 = 1 :LED6 = 0 :
LED7 = 0
PORTB=%11011010
ENDIF

IF SEQ = 6 THEN
LED1 = 0 :LED2 = 0 :LED3 = 0 :LED4 = 0 :LED5 = 0 :LED6 = 1 :
LED7 = 0
PORTB=%11111010
ENDIF

IF SEQ = 7 THEN
LED1 = 0 :LED2 = 0 :LED3 = 0 :LED4 = 0 :LED5 = 0 :LED6 = 0 :
LED7 = 1
PORTB=%00001110
ENDIF

IF SEQ = 8 THEN
LED1 = 1 :LED2 = 0 :LED3 = 0 :LED4 = 0 :LED5 = 1 :LED6 = 0 :
LED7 = 1
PORTB=%11111111
ENDIF

IF SEQ = 9 THEN
LED1 = 0:LED2 = 1 :LED3 = 0 :LED4 = 0 :LED5 = 0 :LED6 = 1 :
LED7 = 0
PORTB=%11011110

ENDIF
PAUSE 100
return

HOW TO USE MCB AS ENABLE AS WELL AS DISABLE?

From the manual.

INPUT Make pin an input.
OUTPUT Make pin an output

Also PBP convention:-

MCB VAR PORTA.2

Symbol is Stamp compatibility, not that it really matters if you so wish. :)

You also have missing parameters in first lines for ADCON, TRIS etc either % or 0 or 1's

Quote:

---

FOR MCB= 1 TO 0 STEP -1
PORTB=1
PORTC=1
MCB=MCB+1
NEXT

---

At first glance, this will run forever.

But, MCB is a bit; it can be 0 or 1. What happens first time through the loop when 1 is added to MCB when it is 1?

Robert

In a loop (for/ next in this case) MCB will increment/ decrement by the step value automatically - no need to add or subtract the value. As:

For LP = 0 to -1 step -1
NOP
Next LP

LP will be set to 0 the first time through, "loop" and set the value of LP to -1, repeat the enclosed code, and then exit because the "to" condition (LP= -1) is met. Manipulating LP manually is not necessary and only bungs up the sequence. In the case where you subtract 1 from MCB: The initial loop starts with LP=0, in the code you reduce MCB to -1 (by subtracting 1), so the exit condition is met and the "loop" fails to repeat. NONE of the looping code is ever executed with LP equal to -1.