;****************** Constant Definitions ******************
  symbol  control   = outpinsA  ;A.0 = BC1, A.1 = BDIR
  symbol  bus       = outpinsB
  
  ;AY-8910 control codes and register addresses
  symbol  inactive  = %00000000 
  symbol  latchData = %00000010
  symbol  latchAddr = %00000011   
  symbol  Reg7      = %00000111 
  symbol  Reg15     = %00001111 ;LED on IOB
  symbol  IOBOut    = %10111111 ;IOB data direction code  
  
  symbol  LED_On    = %00000001
  symbol  LED_Off   = %00000000


;********************** Main Program **********************
pgm:
  dirsA = %11111111       ;make all output
  dirsB = %11111111       ;make all output

  ;set up the AY Port B for output
  bus = Reg7              ;set address to register 7
  control = latchAddr     ;latch the address
  control = inactive    
  bus = IOBOut            ;make Port IOB output
  control = latchData     ;latch data
  control = inactive
  
  main:
    bus = Reg15           ;Turn on LED
    control = latchAddr
    control = inactive 
    bus = LED_on            
    control = latchData
    control = inactive
    pause 500
    
    bus = Reg15           ;Turn off LED
    control = latchAddr
    control = inactive 
    bus = LED_off       
    control = latchData
    control = inactive
    pause 500  
  
  goto main               ;and repeat forever
end