安路SparkRoad实现vga显示屏
本帖最后由 冒险武者 于 2022-5-17 23:06 编辑<p>VGA(Video Graphics Adapter)接口也是D-Sub接口的俗称，是一种采用模拟信号传输的接口；VGA指的是显示器640X480等显示模式，VGA技术的应用还主要基于VGA显示卡的计算机、笔记本等设备；上面共有 15 针孔，分成三排，每排五个。比较重要的是RGB 彩色分量信号和 扫描同步信号 HSYNC 和 VSYNC 针。</p>
<p></p>
<p>扫描时序如下所示：</p>
<p> </p>
<p>现在就用FPGA实现VGA功能</p>
<pre>
<code>// Define colors RGB--8|8|8
`define RED 24'hFF0000
`define GREEN 24'h00FF00
`define BLUE 24'h0000FF
`define WHITE 24'hFFFFFF
`define BLACK 24'h000000
`define YELLOW 24'hFFFF00
`define CYAN 24'hFF00FF
`define ROYAL 24'h00FFFF
// Define Display Mode
module vga_dis
#(
parameter H_DISP = 800,
parameter V_DISP = 600
)
(
inputwire clk,
inputwire clk_108m,
inputwire rst_n,
//user interface
output wire lcd_xpos, //lcd horizontal coordinate
output wire lcd_ypos, //lcd vertical coordinate
// output wire lcd_en ,
inputwire usr_data, //lcd datard_n,
//localbus
inputwire cpu_cs_n,
inputwire cpu_wr_n,
inputwire cpu_rd_n,
inputwirecpu_addr,
inputwire cpu_datain,
output reg cpu_dataout,
//lcd interface
output wire lcd_dclk, //lcd pixel clock
output wire lcd_hs, //lcd horizontal sync
output wire lcd_vs, //lcd vertical sync
output wire lcd_en, //lcd display enable
output wire lcd_rgb //lcd display data
);
regvga_mode;
reg usr_lcd_data ;
reg lcd_data ;//lcd data
wire lcd_xpos; //lcd horizontal coordinate
wire lcd_ypos; //lcd vertical coordinate
//read
always@(posedge clk or posedge rst_n)
begin
if(rst_n == 1'b0)
begin
cpu_dataout<=16'h0000;
end
else if((cpu_cs_n == 1'b0)&&(cpu_rd_n == 1'b0))
begin
case(cpu_addr)
8'h00:cpu_dataout<=vga_mode ;
8'h01:cpu_dataout<=usr_lcd_data ;
8'h02:cpu_dataout<=usr_lcd_data ;
default:cpu_dataout<=16'h0000;
endcase
end
else
cpu_dataout<=16'h0000;
end
//read
always@(posedge clk or posedge rst_n)
begin
if(rst_n == 1'b0)
begin
vga_mode<=3'b100;
usr_lcd_data <= 24'h0;
end
else if((cpu_cs_n == 1'b0)&&(cpu_wr_n == 1'b0))
begin
case(cpu_addr)
8'h00:vga_mode<= cpu_datain ;
8'h01:usr_lcd_data<= cpu_datain ;
8'h02:usr_lcd_data<= cpu_datain ;
default: ;
endcase
end
else ;
end
always@(posedge clk_108m or negedge rst_n)
begin
if(!rst_n)
lcd_data <= 24'h0;
else
begin
case(vga_mode)
3'b000:begin
if (lcd_ypos >= 0 && lcd_ypos < (V_DISP/8)*1)
lcd_data <= `RED;
else if(lcd_ypos >= (V_DISP/8)*1 && lcd_ypos < (V_DISP/8)*2)
lcd_data <= `GREEN;
else if(lcd_ypos >= (V_DISP/8)*2 && lcd_ypos < (V_DISP/8)*3)
lcd_data <= `BLUE;
else if(lcd_ypos >= (V_DISP/8)*3 && lcd_ypos < (V_DISP/8)*4)
lcd_data <= `WHITE;
else if(lcd_ypos >= (V_DISP/8)*4 && lcd_ypos < (V_DISP/8)*5)
lcd_data <= `BLACK;
else if(lcd_ypos >= (V_DISP/8)*5 && lcd_ypos < (V_DISP/8)*6)
lcd_data <= `YELLOW;
else if(lcd_ypos >= (V_DISP/8)*6 && lcd_ypos < (V_DISP/8)*7)
lcd_data <= `CYAN;
else
lcd_data <= `ROYAL;
end
3'b001:begin
if (lcd_xpos >= 0 && lcd_xpos < (H_DISP/8)*1)
lcd_data <= `RED;
else if(lcd_xpos >= (H_DISP/8)*1 && lcd_xpos < (H_DISP/8)*2)
lcd_data <= `GREEN;
else if(lcd_xpos >= (H_DISP/8)*2 && lcd_xpos < (H_DISP/8)*3)
lcd_data <= `BLUE;
else if(lcd_xpos >= (H_DISP/8)*3 && lcd_xpos < (H_DISP/8)*4)
lcd_data <= `WHITE;
else if(lcd_xpos >= (H_DISP/8)*4 && lcd_xpos < (H_DISP/8)*5)
lcd_data <= `BLACK;
else if(lcd_xpos >= (H_DISP/8)*5 && lcd_xpos < (H_DISP/8)*6)
lcd_data <= `YELLOW;
else if(lcd_xpos >= (H_DISP/8)*6 && lcd_xpos < (H_DISP/8)*7)
lcd_data <= `CYAN;
else
lcd_data <= `ROYAL;
end
3'b010:begin
lcd_data <= lcd_xpos * lcd_ypos;
end
3'b011:begin
if(lcd_ypos < V_DISP/2)
lcd_data <= {lcd_ypos, lcd_ypos, lcd_ypos};
else
lcd_data <= {lcd_xpos, lcd_xpos, lcd_xpos};
end
3'b100:begin
lcd_data <= usr_data;
end
3'b101:begin
lcd_data <= usr_lcd_data;
end
default lcd_data <= lcd_data;
endcase
end
end
vga_driu_vga_dri
(
// Input
.clk (clk_108m ),
.rst_n (rst_n ),
.lcd_data (lcd_data ),
// Output
.lcd_dclk (lcd_dclk ),
.lcd_hs (lcd_hs ),
.lcd_vs (lcd_vs ),
.lcd_en (lcd_en ),
.lcd_rgb (lcd_rgb ),
.lcd_xpos (lcd_xpos ),
.lcd_ypos (lcd_ypos )
);
endmodule</code></pre>
<p> </p>
<p>同样是采用localbus接口，可以设置不同的显示模式，目前实现5种模式实现VGA的显示样式，同时也可以通过串口，显示不同的颜色。</p>
<p> </p>
<p>ff867add12181b3277f6c38722db2aa2<br />
</p>
能把显示驱动起来，接下来的东西就更好玩了吧。
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