File size: 2,971 Bytes
ed7714b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | //
// video freeze with sync
// (C) Alexey Melnikov
//
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
module video_freezer
(
input clk,
output sync,
input freeze,
input hs_in,
input vs_in,
input hbl_in,
input vbl_in,
output hs_out,
output vs_out,
output hbl_out,
output vbl_out
);
sync_lock #(33) vs_lock
(
.clk(clk),
.sync_in(vs_in),
.sync_out(vs_out),
.de_in(vbl_in),
.de_out(vbl_out),
.freeze(freeze)
);
wire sync_pt;
sync_lock #(21) hs_lock
(
.clk(clk),
.sync_in(hs_in),
.sync_out(hs_out),
.de_in(hbl_in),
.de_out(hbl_out),
.freeze(freeze),
.sync_pt(sync_pt)
);
reg sync_o;
always @(posedge clk) begin
reg old_hs, old_vs;
reg vs_sync;
old_vs <= vs_out;
if(~old_vs & vs_out) vs_sync <= 1;
if(sync_pt & vs_sync) begin
vs_sync <= 0;
sync_o <= ~sync_o;
end
end
assign sync = sync_o;
endmodule
module sync_lock #(parameter WIDTH)
(
input clk,
input sync_in,
input de_in,
output sync_out,
output de_out,
input freeze,
output sync_pt,
output valid
);
reg [WIDTH-1:0] f_len, s_len, de_start, de_end;
reg sync_valid;
reg old_sync;
always @(posedge clk) old_sync <= sync_in;
always @(posedge clk) begin
reg [WIDTH-1:0] cnti;
reg f_valid;
reg old_de;
cnti <= cnti + 1'd1;
if(~old_sync & sync_in) begin
if(sync_valid) f_len <= cnti;
f_valid <= 1;
sync_valid <= f_valid;
cnti <= 0;
end
if(old_sync & ~sync_in & sync_valid) s_len <= cnti;
old_de <= de_in;
if(~old_de & de_in & sync_valid) de_start <= cnti;
if(old_de & ~de_in & sync_valid) de_end <= cnti;
if(freeze) {f_valid, sync_valid} <= 0;
end
reg sync_o, de_o, sync_o_pre;
always @(posedge clk) begin
reg [WIDTH-1:0] cnto;
cnto <= cnto + 1'd1;
if(old_sync & ~sync_in & sync_valid) cnto <= s_len + 2'd2;
if(cnto == f_len) cnto <= 0;
sync_o_pre <= (cnto == (s_len>>1)); // middle in sync
if(cnto == f_len) sync_o <= 1;
if(cnto == s_len) sync_o <= 0;
if(cnto == de_start) de_o <= 1;
if(cnto == de_end) de_o <= 0;
end
assign sync_out = freeze ? sync_o : sync_in;
assign valid = sync_valid;
assign sync_pt = sync_o_pre;
assign de_out = freeze ? de_o : de_in;
endmodule
|