XDEF	Circulation
	XREF	__SEG_END_SSTACK,show_temperature,display_string,disp,dc_on,pw_set,PORT_T,PORT_S
	
Circulation: ;push register and accumulator values for retention                   
            PSHA
            PSHB
            PSHD
            PSHX
            PSHY
            

           ;bail if the password is not set
           LDAA   pw_set
           CMPA   #$FF
           LBNE   Return
            
           ;
           ;run the motor and stuff like that here
           ;(the motor should run whether or not
           ;the temperature is displayed) 
           ;
           LDAA   dc_on
           CMPA   #$FF
           BNE    PulseOff

PulseOn:
            BSET  PORT_T,#$8       ;set bit 3 of Port T
            ;MOVB  #$0F,PORT_S
            BRA   PrintTemperature ;exit the interrupt routine

PulseOff:
            BCLR  PORT_T,#$8       ;clear bit 3 of Port T
            ;MOVB  #$F0,PORT_S
            BRA   PrintTemperature ;exit the interrupt 
             
PrintTemperature:

           ;check if the temperature should show
           LDAA  show_temperature
           CMPA  #$00
           LBEQ   Return
           
          ;print the temperature
           movb #'T',disp
           movb #'e',disp+1
           movb #'m',disp+2
           movb #'p',disp+3
           movb #'e',disp+4
           movb #'r',disp+5
           movb #'a',disp+6
           movb #'t',disp+7
           movb #'u',disp+8
           movb #'r',disp+9
           movb #'e',disp+10
           movb #':',disp+11
           movb #' ',disp+12
           movb #' ',disp+13
           movb #' ',disp+14
           movb #' ',disp+15
           ;next line
           movb #'X',disp+16
           movb #'Y',disp+17
           movb #'Z',disp+18
           movb #' ',disp+19
           movb #'d',disp+20
           movb #'e',disp+21
           movb #'g',disp+22
           movb #'r',disp+23
           movb #'e',disp+24
           movb #'e',disp+25
           movb #'s',disp+26
           movb #' ',disp+27
           movb #' ',disp+28
           movb #' ',disp+29
           movb #' ',disp+30
           movb #' ',disp+31
           movb #0,disp+32    ;string terminator, acts like '\0'
           
           LDD   #disp         ;both of these steps are necessary to
           jsr  display_string ;print to the LCD screen          
    
Return:     ;restore registers and accumulators
           PULY
           PULX
           PULD
           PULB
           PULA
           
           RTS