Off the top of my head........untested !!!!!!

Use nibbles

value = 2B

nibble = value >>4
go do lookup
nibble= value & %1111
go do lookup

findascii
Lookdown nibble,["0123456789ABCDEF"],asciichar


so
2B is binary %101011

shift right 4 =%0010
do the look down which returns 2 in ascii

nibble= value & %1111 = %1011
do the look down which returns B in ascii


Lookdown lownibble,["0123456789ABCDEF"],asciichar