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1 | ////////////////////////////////////////////////////////////////////// |
2 | //// //// |
3 | //// File name: pci_target32_clk_en.v //// |
4 | //// //// |
5 | //// This file is part of the "PCI bridge" project //// |
6 | //// http://www.opencores.org/cores/pci/ //// |
7 | //// //// |
8 | //// Author(s): //// |
9 | //// - Tadej Markovic, tadej@opencores.org //// |
10 | //// //// |
11 | //// All additional information is avaliable in the README.txt //// |
12 | //// file. //// |
13 | //// //// |
14 | //// //// |
15 | ////////////////////////////////////////////////////////////////////// |
16 | //// //// |
17 | //// Copyright (C) 2000 Tadej Markovic, tadej@opencores.org //// |
18 | //// //// |
19 | //// This source file may be used and distributed without //// |
20 | //// restriction provided that this copyright statement is not //// |
21 | //// removed from the file and that any derivative work contains //// |
22 | //// the original copyright notice and the associated disclaimer. //// |
23 | //// //// |
24 | //// This source file is free software; you can redistribute it //// |
25 | //// and/or modify it under the terms of the GNU Lesser General //// |
26 | //// Public License as published by the Free Software Foundation; //// |
27 | //// either version 2.1 of the License, or (at your option) any //// |
28 | //// later version. //// |
29 | //// //// |
30 | //// This source is distributed in the hope that it will be //// |
31 | //// useful, but WITHOUT ANY WARRANTY; without even the implied //// |
32 | //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR //// |
33 | //// PURPOSE. See the GNU Lesser General Public License for more //// |
34 | //// details. //// |
35 | //// //// |
36 | //// You should have received a copy of the GNU Lesser General //// |
37 | //// Public License along with this source; if not, download it //// |
38 | //// from http://www.opencores.org/lgpl.shtml //// |
39 | //// //// |
40 | ////////////////////////////////////////////////////////////////////// |
41 | // |
42 | // CVS Revision History |
43 | // |
44 | // $Log: pci_target32_clk_en.v,v $ |
45 | // Revision 1.1 2007-03-20 17:50:56 sithglan |
46 | // add shit |
47 | // |
48 | // Revision 1.4 2003/01/27 16:49:31 mihad |
49 | // Changed module and file names. Updated scripts accordingly. FIFO synchronizations changed. |
50 | // |
51 | // Revision 1.3 2002/02/01 15:25:12 mihad |
52 | // Repaired a few bugs, updated specification, added test bench files and design document |
53 | // |
54 | // Revision 1.2 2001/10/05 08:14:30 mihad |
55 | // Updated all files with inclusion of timescale file for simulation purposes. |
56 | // |
57 | // Revision 1.1.1.1 2001/10/02 15:33:47 mihad |
58 | // New project directory structure |
59 | // |
60 | // |
61 | |
62 | // module is used to separate logic which uses criticaly constrained inputs from slower logic. |
63 | // It is used to synthesize critical timing logic separately with faster cells or without optimization |
64 | |
65 | // synopsys translate_off |
66 | `include "timescale.v" |
67 | // synopsys translate_on |
68 | |
69 | module pci_target32_clk_en |
70 | ( |
71 | addr_phase, |
72 | config_access, |
73 | addr_claim_in, |
74 | pci_frame_in, |
75 | state_wait, |
76 | state_transfere, |
77 | state_default, |
78 | clk_enable |
79 | ); |
80 | |
81 | input addr_phase ; // indicates registered address phase on PCI bus |
82 | input config_access ; // indicates configuration access |
83 | input addr_claim_in ; // indicates claimed input PCI address |
84 | input pci_frame_in ; // critical constrained input signal |
85 | input state_wait ; // indicates WAIT state of FSM |
86 | input state_transfere ; // indicates TRANSFERE state of FSM |
87 | input state_default ; // indicates DEFAULT state of FSM |
88 | |
89 | output clk_enable ; // FSM clock enable output |
90 | |
91 | |
92 | // clock enable signal when FSM is in IDLE state |
93 | wire s_idle_clk_en = ((addr_phase && config_access) || |
94 | (addr_phase && ~config_access && addr_claim_in)) ; |
95 | |
96 | // clock enable signal when FSM is in WAIT state or in DEFAULT state |
97 | wire s_wait_clk_en = (state_wait || state_default) ; |
98 | |
99 | // clock enable signal when FSM is in TRANSFERE state |
100 | wire s_tran_clk_en = (state_transfere && pci_frame_in) ; |
101 | |
102 | |
103 | // Clock enable signal for FSM with preserved hierarchy for minimum delay! |
104 | assign clk_enable = (s_idle_clk_en || s_wait_clk_en || s_tran_clk_en) ; |
105 | |
106 | |
107 | endmodule |