|  | // Copyright (C) 2020-2021  The SymbiFlow Authors. | 
|  | // | 
|  | // Use of this source code is governed by a ISC-style | 
|  | // license that can be found in the LICENSE file or at | 
|  | // https://opensource.org/licenses/ISC | 
|  | // | 
|  | // SPDX-License-Identifier:ISC | 
|  |  | 
|  | module inpad ( | 
|  | output Q, | 
|  | (* iopad_external_pin *) | 
|  | input  P | 
|  | ); | 
|  | assign Q = P; | 
|  | endmodule | 
|  |  | 
|  | module outpad ( | 
|  | (* iopad_external_pin *) | 
|  | output P, | 
|  | input  A | 
|  | ); | 
|  | assign P = A; | 
|  | endmodule | 
|  |  | 
|  | module ckpad ( | 
|  | output Q, | 
|  | (* iopad_external_pin *) | 
|  | input  P | 
|  | ); | 
|  | assign Q = P; | 
|  | endmodule | 
|  |  | 
|  | module bipad ( | 
|  | input  A, | 
|  | input  EN, | 
|  | output Q, | 
|  | (* iopad_external_pin *) | 
|  | inout  P | 
|  | ); | 
|  | assign Q = P; | 
|  | assign P = EN ? A : 1'bz; | 
|  | endmodule | 
|  |  | 
|  |  | 
|  | module dff ( | 
|  | output reg Q, | 
|  | input D, | 
|  | (* clkbuf_sink *) | 
|  | input CLK | 
|  | ); | 
|  | parameter [0:0] INIT = 1'b0; | 
|  | initial Q = INIT; | 
|  | always @(posedge CLK) Q <= D; | 
|  | endmodule | 
|  |  |