i cant understand the programming table...

i need to implement a 8-1 MUX using 2^3X4 and 2^3X1 proms

where there is a chip select input in the MUX

here is the solution of the circuit and the programming tables
i cant understand those minux signs in the table that represents 2,3,4,5 proms

**broken link removed**

transgalactic said:

i cant understand those minux signs in the table that represents 2,3,4,5 proms

Click to expand...

I think those mean "don't care" ie: The input can be either 0 or 1 and the output data should remain the same.