Temperature does not go below 0

[amodpathak]

IAM MAKING TEMPERATURE CONTROLLER USING ntc THERMISTOR FROM -10 DEGREE TO 50 DEGREE.BUT MY TEMPERATURE IS NOT GOING BELOW 0. PLS CHECK MY CODE AND GUIDE ME.THANKS

 DG1 VAR BYTE       
 DG2 VAR BYTE    
 DG3 VAR BYTE
 DIGIT VAR BYTE
 DG VAR BYTE
 COUNTT VAR BYTE
 
 NUMB VAR WORD
 N VAR WORD
 adval var word
 temp var word
 TEMPP VAR WORD
 
 ADCON1=%10000000
 adcon0=%00000101 
 TRISA=1           
 TRISB=%00111000   
 TRISC=0           
 
 numb=0
 gosub mread
 'n=numb
 GOSUB DIGITCALC   
'-------------------------------------------------------------------------


 MAIN1:


 GOSUB DISPLAY
 
 IF PORTB.3=1 THEN MREAD
 
 IF PORTB.3=0 THEN MAIN
 
   
 
 
 GOTO MAIN1
 
 
 






'-------------------------------------------------------------------------
                     MAIN:


                        ADCON0.2=1  


                       GO:
                        IF ADCON0.2=1 THEN GO 
     
                        adval.HIGHBYTE = ADRESH                   
                        adval.lowbyte = ADRESL
                        temp=adval 
                        N=temp
                        gosub display
                        gosub digitcalc
                        
                        
                        If adval>NUMB then PORTB.7=0
                        IF ADVAL< NUMB-5 THEN PORTB.7=1
                        GOTO MAIN1




                    '_____________________________________


                     UP:
                     IF NUMB=50 THEN MAIN
                     NUMB=NUMB+1
                     N=NUMB
                     GOSUB DIGITCALC
                     IF PORTB.4=1 THEN MEMORY
                     GOTO MAIN1
                     
                     
                     memory:
                     WRITE 0,numb.HighByte    
                     
                     WRITE 1,numb.LowByte     
                     
                     GOTO MAIN1


                    '_____________________________________


                     DOWN:
                     IF NUMB=-10 THEN MAIN      'MIN LIMIT
                     NUMB=NUMB-1
                     N=NUMB
                     GOSUB DIGITCALC
                     IF PORTB.5=1 THEN MEMORY
                     GOTO MAIN1
                     
                     
                    '_____________________________________
                    MREAD:
                    READ 0,numb.HighByte    
                                                    
                    READ 1,numb.LowByte  
                    
                    n=numb
                    gosub digitcalc
                    IF PORTB.4=1 THEN UP
                    IF PORTB.5=1 THEN DOWN
                    goto main1 
                    
                    
                    
                    
          
                    
                    
                    
                      
                      
                     
       ___________________________________________________
        DISPLAY:
        
        
        FOR COUNTT=0 TO 99


        PORTC=DG1
        PORTB.2=1
        PAUSEUS 300
        PORTB.2=0


        PORTC=DG2
        PORTB.1=1
        PAUSEUS 300
        PORTB.1=0


        PORTC=DG3
        PORTB.0=1
        PAUSEUS 300 
        PORTB.0=0


        NEXT COUNTT


        RETURN


       '________________________________________________________________






'__________________________________________________________________________
DIGITCALC:


DIGIT=0
LP1:
IF N<100 THEN DS1
N=N-100
DIGIT=DIGIT+1
GOTO LP1
        DS1:
        GOSUB FND
        DG1=DG
       


DIGIT=0
LP2:
IF N<10 THEN DS2
N=N-10
DIGIT=DIGIT+1
GOTO LP2


        DS2:
        GOSUB FND
        DG2=DG
        


DIGIT=N
GOSUB FND
DG3=DG




 
RETURN








'__________________________________________________________________________




'__________________________________________________________________________
FND:








FND0:
IF DIGIT>0 THEN FND1
DG=$7E                       '%0111 1110      
GOTO FNDEND


FND1:
IF DIGIT>1 THEN FND2
DG=$48                       '%0100 1000      
GOTO FNDEND


FND2:
IF DIGIT>2 THEN FND3
DG=$3D                       '%0011 1101      
GOTO FNDEND


FND3:
IF DIGIT>3 THEN FND4
DG=$6D                       '%0110 1101      
GOTO FNDEND


FND4:
IF DIGIT>4 THEN FND5
DG=$4B                       '%0100 0011      
GOTO FNDEND


FND5:
IF DIGIT>5 THEN FND6
DG=$67                       '%0110 0111      
GOTO FNDEND


FND6:
IF DIGIT>6 THEN FND7
DG=$77                       '%0111 0111      
GOTO FNDEND


FND7:
IF DIGIT>7 THEN FND8
DG=$4C                       '%0100 1100      
GOTO FNDEND


FND8:
IF DIGIT>8 THEN FND9
DG=$7F                       '%0111 1111      
GOTO FNDEND


FND9:
DG=$6F                       '%0110 1111      


FNDEND:
RETURN

'_________________________________________________ _________________________