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//////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2011, Andrew "bunnie" Huang
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation and/or
// other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
// SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
//////////////////////////////////////////////////////////////////////////////
`timescale 1 ns / 1ps
module boxtiming (
input wire pclk,
input wire rstin,
input wire vsync,
input wire hsync,
input wire sync_pol, // 0 means active 0, 1 means active 1
input wire de,
input wire cv,
input wire [11:0] hpos,
input wire [11:0] hsize,
input wire [11:0] vpos,
input wire [11:0] vsize,
output reg box_active
);
reg [11:0] hcount;
reg [11:0] vcount;
reg hsync_v; // active when high
reg hsync_v2;
reg vsync_v;
reg vsync_v2;
reg de_d;
reg active;
wire hsync_rising;
wire vsync_rising;
wire de_rising;
wire de_falling;
always @(posedge pclk or posedge rstin) begin
if( rstin ) begin
hsync_v <= 0;
vsync_v <= 0;
hsync_v2 <= 0;
vsync_v2 <= 0;
de_d <= 0;
end else begin
de_d <= de;
if( cv ) begin
hsync_v <= hsync ^ !sync_pol;
vsync_v <= vsync ^ !sync_pol;
end else begin
hsync_v <= hsync_v;
vsync_v <= vsync_v;
end
hsync_v2 <= hsync_v; // just a delayed version
vsync_v2 <= vsync_v;
end // else: !if( rstin )
end // always @ (posedge pclk or posedge rstin)
assign hsync_rising = hsync_v & !hsync_v2;
assign vsync_rising = vsync_v & !vsync_v2;
assign de_rising = de & !de_d;
assign de_falling = !de & de_d;
always @(posedge pclk or posedge rstin) begin
if( rstin ) begin
hcount <= 0;
end else begin
if( de_rising ) begin
hcount <= 12'b0000_0000_0000;
end else begin
if( de ) begin
hcount <= hcount + 12'b0000_0000_0001;
end else begin
hcount <= hcount;
end
end
end // else: !if( rstin )
end // always @ (posedge pclk or posedge rstin)
always @(posedge pclk or posedge rstin) begin
if( rstin ) begin
vcount <= 0;
end else begin
if( vsync_rising ) begin
vcount <= 12'b0000_0000_0000;
end else begin
if( de_falling ) begin // this may be a bug but I think it's worked around elsewhere
vcount <= vcount + 12'b0000_0000_0001;
end else begin
vcount <= vcount;
end
end
end // else: !if( rstin )
end // always @ (posedge pclk or posedge rstin)
always @(posedge pclk or posedge rstin) begin
if( rstin ) begin
active <= 0;
end else begin
if( (hcount >= hpos) && (hcount < (hpos + hsize)) &&
(vcount >= vpos) && (vcount < (vpos + vsize)) ) begin
active <= 1'b1;
end else begin
active <= 1'b0;
end
end
box_active <= active;
end // always @ (posedge pclk or posedge rstin)
endmodule
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