A 4 place binary number, from 0000 to 1111 can also be described in base sixteen (called hexadecimal).
0000 = 0 (hex)
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = A
1001 = B
1010 = C
1011 = D
1100 = E
1101 = F
1110 = G
1111 = H
See that each hex number creates a unique combination of 'bits' when your control converts the number. It is kind of a code puzzle: you determine which sequence of bits you want, and then enter in the hex value that gives you the magic combo.
So, your 8 bit binary number in your controller can be described as a two place hexadecimal, or 00 hex.
Any value in either the left or the right 4 bits, will be equivalent to one hex number, from 0 to H.
So if there is a binary value in the left 4 digits, convert that to the hex value. Ditto on the right 4 bits. If no value (all zeros), then it is also 0 in hex.
I suppose your control could also use Octal, which would be base 8. That I don't know the numbering scheme, but if only there was this magic box that a guy could use to search the archives of the world with....