Creat an interface .Define modport to specifies direction. These are used to connect testbench environment and dut in top module.
CODE:interface
`ifndef INTF
`define INTF
interface switch_if(); bit data_status; bit [7:0] data_in; wire [3:0][7:0] data_out; wire [3:0] ready; bit [3:0] read; bit [7:0] mem_data; bit [1:0] mem_add; bit reset; bit mem_en; bit mem_rd_wr; bit clock;