' This program creates an 8-LED Larson scanner on the P2 Eval board

dat     org

ls_fwd      mov ledpin, #56     ' start with p56
            mov cycles, #7      ' light 7 going up
.loop       drvl    ledpin          ' led on
            waitx   ##20_000_000/8      ' wait 1/8 second
            drvh    ledpin          ' led off
            add ledpin, #1      ' next pin
            djnz    cycles, #.loop      ' done? 

ls_rev      mov ledpin, #63     ' start with p63
            mov cycles, #7      ' light 7 going down
.loop       drvl    ledpin
            waitx   ##20_000_000/8
            drvh    ledpin
            sub ledpin, #1
            djnz    cycles, #.loop

            jmp #ls_fwd


ledpin  res 1
cycles  res 1