module Internal_bus(bf_out,ctr0_select,ctr0_RW,bf_in);
input [7:0]bf_out; //Bidirectional buffer output here declared as input
input ctr0_select,ctr0_RW;
output [7:0]bf_in;//lead to counter data input
assign bf_in[7:0] = (ctr0_select == 1'b1 && ctr0_RW == 1'b1)?(bf_out[7:0]:8'bXXXXXXXX);