Hello Mr. Frank Jin,

Another da a (decimal adjust) method of converting a byte value to Ascii is shown below.

BINTOASC:
anl a,#00fh ; Keep only Low Bits
add a,#090h ; Add 144
da a ; Decimal Adjust
addc a,#040h ; Add 64
da a ; Decimal Adjust
ret ; Return To Caller

Good luck,

Charles Bannister