1 module touch_tcon (
  2   input             iCLK,             // LCD display clock
  3   input             iRST_n,           // systen reset
  4   // SDRAM SIDE
  5   input [15:0]      iREAD_DATA1,      // R and G  color data form sdram    
  6   input [15:0]      iREAD_DATA2,      // B color data form sdram
  7   output            oREAD_SDRAM_EN,   // read sdram data control signal
  8   //LCD SIDE
  9   output  reg       oHD,              // LCD Horizontal sync
10   output  reg       oVD,              // LCD Vertical sync
11   output  reg       oDEN,             // LCD Data Enable
12   output  reg [7:0] oLCD_R,           // LCD Red color data
13   output  reg [7:0] oLCD_G,           // LCD Green color data
14   output  reg [7:0] oLCD_B            // LCD Blue color data
15 );
16 
17 parameter H_LINE = 1056;
18 parameter V_LINE = 525;
19 parameter Hsync_Blank = 216;
20 parameter Hsync_Front_Porch = 40;
21 parameter Vertical_Back_Porch = 35;
22 parameter Vertical_Front_Porch = 10;
23 
24 reg   [10:0]  x_cnt; 
25 reg   [9:0]   y_cnt;
26 wire  [7:0]   read_red;
27 wire  [7:0]   read_green;
28 wire  [7:0]   read_blue;
29 wire          display_area;
30 reg           mhd;
31 reg           mvd;
32 reg           mden;
33 
34 // This signal control reading data form SDRAM , if high read color data form sdram  .
35 assign  oREAD_SDRAM_EN = ( (x_cnt>Hsync_Blank-2)&&
36                            (x_cnt<(H_LINE-Hsync_Front_Porch-1))&&
37                            (y_cnt>(Vertical_Back_Porch-1))&&
38                            (y_cnt<(V_LINE - Vertical_Front_Porch))
39                          )?  1'b1 : 1'b0;
40 
41 // This signal indicate the lcd display area .
42 assign  display_area = ((x_cnt>(Hsync_Blank-1)&& //>215
43                         (x_cnt<(H_LINE-Hsync_Front_Porch))&& //< 1016
44                         (y_cnt>(Vertical_Back_Porch-1))&& 
45                         (y_cnt<(V_LINE - Vertical_Front_Porch))
46                        ))  ? 1'b1 : 1'b0;
47 
48 assign  read_red    = display_area ? iREAD_DATA2[9:2] : 8'b0;
49 assign  read_green  = display_area ? {iREAD_DATA1[14:10],iREAD_DATA2[14:12]}: 8'b0;
50 assign  read_blue   = display_area ? iREAD_DATA1[9:2] : 8'b0;
51 
52 / x  y counter  and lcd hd generator //
53 always@(posedge iCLK or negedge iRST_n) begin
54   if (!iRST_n) begin
55     x_cnt <= 11'd0;
56     mhd   <= 1'd0;
57   end
58   else if (x_cnt == (H_LINE-1)) begin
59     x_cnt <= 11'd0;
60     mhd   <= 1'd0;
61   end
62   else begin
63     x_cnt <= x_cnt + 11'd1;
64     mhd  <= 1'd1;
65   end
66 end
67 
68 always@(posedge iCLK or negedge iRST_n) begin
69   if (!iRST_n)
70     y_cnt <= 10'd0;
71   else if (x_cnt == (H_LINE-1)) begin
72     if (y_cnt == (V_LINE-1))
73       y_cnt <= 10'd0;
74     else
75       y_cnt <= y_cnt + 10'd1;   
76   end
77 end
78 
79 // touch panel timing //
80 always@(posedge iCLK  or negedge iRST_n) begin
81   if (!iRST_n)
82     mvd  <= 1'b1;
83   else if (y_cnt == 10'd0)
84     mvd  <= 1'b0;
85   else
86     mvd  <= 1'b1;
87 end
88 
89 always@(posedge iCLK  or negedge iRST_n) begin
90   if (!iRST_n)
91     mden  <= 1'b0;
92   else if (display_area)
93     mden  <= 1'b1;
94   else
95     mden  <= 1'b0;
96 end
97 
98 always@(posedge iCLK or negedge iRST_n) begin
99   if (!iRST_n) begin
100     oHD     <= 1'd0;
101     oVD     <= 1'd0;
102     oDEN    <= 1'd0;
103     oLCD_R  <= 8'd0;
104     oLCD_G  <= 8'd0;
105     oLCD_B  <= 8'd0;
106   end
107   else begin
108     oHD     <= mhd;
109     oVD     <= mvd;
110     oDEN    <= mden;
111    
112     if (coord_x > 200 && coord_x < 320 && 
113         coord_y > 200 && coord_y < 240) begin
114       oLCD_R = 10'h000;
115       oLCD_G = 10'h000;
116       oLCD_B = 10'h000;
117     end
118     else begin
119       oLCD_R  <= read_red;
120       oLCD_G  <= read_green;
121       oLCD_B  <= read_blue;
122     end 
123   end
124 end
125 
126 reg [9:0] coord_x;
127 reg [9:0] coord_y;
128 
129 always@(posedge iCLK or negedge iRST_n) begin
130   if (!iRST_n) begin
131     coord_x     <= 0;
132     coord_y     <= 0;
133   end
134   else begin
135     if (display_area) begin
136       coord_x     <= x_cnt - (Hsync_Blank-1);
137       coord_y     <= y_cnt - (Vertical_Back_Porch-1);
138     end
139   end
140 end
141 
142 endmodule

reg [9:0] coord_x;
reg [9:0] coord_y;

always@(posedge iCLK or negedge iRST_n) begin
  if (!iRST_n) begin
    coord_x     <= 0;
    coord_y     <= 0;
  end
  else begin
    if (display_area) begin
      coord_x     <= x_cnt - (Hsync_Blank-1);
      coord_y     <= y_cnt - (Vertical_Back_Porch-1);
    end
  end
end

// This signal indicate the lcd display area .
assign  display_area = ((x_cnt>(Hsync_Blank-1)&& //>215
                        (x_cnt<(H_LINE-Hsync_Front_Porch))&& //< 1016
                        (y_cnt>(Vertical_Back_Porch-1))&& 
                        (y_cnt<(V_LINE - Vertical_Front_Porch))
                       ))  ? 1'b1 : 1'b0;

if (coord_x > 200 && coord_x < 320 && 
    coord_y > 200 && coord_y < 240) begin
  oLCD_R = 10'h000;
  oLCD_G = 10'h000;
  oLCD_B = 10'h000;
end
else begin
  oLCD_R  <= read_red;
  oLCD_G  <= read_green;
  oLCD_B  <= read_blue;
end