Verilog HDL Example Instantiation

module test (datain_h, datain_l, oe, outclock, dataout, dataout_n);
       input   datain_h;
       input   datain_l;
       input   outclock;
       input oe;
       output   dataout;
       output   dataout_n;
       wire tmp_out;
       wire tmp_oe;
 
       my_altddio_out altddio_out_inst (
                                                 .outclock (outclock),
                                                 .datain_h (datain_h),
                                                 .datain_l (datain_l),
                                                 .dataout (tmp_out),
                                                 .aclr (1'b0),
                                                 .aset (1'b0),
                                                 .oe (oe),
                                                 .outclocken (1'b1),
                                                 .oe_out (tmp_oe),
                                                 .sclr (1'b0)
                                           );
 
alt_outbuf_tri_diff my_outbuf (.i (tmp_out), .oe (tmp_oe), .o(dataout), .obar(dataout_n));
defparam my_outbuf.io_standard = "LVDS";
 
endmodule
Important: To successfully perform RTL simulation and formal verification, use lowercase primitive name in instantiation.