基于FPGA的VGA协议实现
基于FPGA的VGA协议实现
一、屏幕上显示彩色条纹
1.创建工程
通过python脚本创建好工程文件夹，然后进行代码编写
2.代码编写
我这里使用了vscode来进行代码编写
上图verilog文件定义了会使用的一些变量
在vga_ctrl中则是控制vga显示的逻辑
代码：
`define vga_800_600
`include "vga_param.v"
module vga_ctrl (
input clk ,
input rst_n ,
input [23:0] data_dis ,
output reg [10:0] h_addr , //数据有效显示区域行地址
output reg [10:0] v_addr , //数据有效显示区域场地址
output reg hsync ,
output reg vsync ,
output reg [7:0] vga_r ,
output reg [7:0] vga_g ,
output reg [7:0] vga_b ,
output reg vga_blk , //VGA消隐信号
output reg vga_clk
);
//参数定义
parameter H_SYNC_STA = 1 ,
H_SYNC_STO = `H_Sync_Time ,
H_DATA_STA = `H_Sync_Time + `H_Back_Porch + `H_Left_Border ,
H_DATA_STO = `H_Sync_Time + `H_Back_Porch + `H_Left_Border + `H_Data_Time ,
V_SYNC_STA = 1 ,
V_SYNC_STO = `V_Sync_Time ,
V_DATA_STA = `V_Sync_Time + `V_Back_Porch + `V_Top_Border ,
V_DATA_STO = `V_Sync_Time + `V_Back_Porch + `V_Top_Border + `V_Data_Time;
//信号定义
reg [11:0] cnt_h_addr ; //行地址计数器
wire add_cnt_h_addr ;
wire end_cnt_h_addr ;
reg [11:0] cnt_v_addr ; //场地址计数器
wire add_cnt_v_addr ;
wire end_cnt_v_addr ;
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
cnt_h_addr <= 1'd0;
end
else if(add_cnt_h_addr)begin
if(end_cnt_h_addr)begin
cnt_h_addr <= 1'd0;
end
else begin
cnt_h_addr <= cnt_h_addr + 1'd1 ;
end
end
end
assign add_cnt_h_addr = 1'd1 ;
assign end_cnt_h_addr = add_cnt_h_addr && cnt_h_addr == `H_Total_Time - 1 ;
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
cnt_v_addr <= 1'd0;
end
else if(add_cnt_v_addr)begin
if(end_cnt_v_addr)begin
cnt_v_addr <= 1'd0;
end
else begin
cnt_v_addr <= cnt_v_addr + 1'd1;
end
end
end
assign add_cnt_v_addr = end_cnt_h_addr;
assign end_cnt_v_addr = add_cnt_v_addr && cnt_v_addr == `V_Total_Time - 1 ;
//行场同步信号
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
hsync <= 1'b1;
end
else if(cnt_h_addr == H_SYNC_STA - 1)begin
hsync <= 1'b0;
end
else if(cnt_h_addr == H_SYNC_STO - 1)begin
hsync <= 1'b1;
end
end
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
vsync <= 1'b1;
end
else if(cnt_v_addr == V_SYNC_STA - 1)begin
vsync <= 1'b0;
end
else if(cnt_v_addr == V_SYNC_STO - 1)begin
vsync <= 1'b1;
end
end
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
vga_clk <= 1'b1;
end
else begin
vga_clk <= ~vga_clk;
end
end
//assign vga_clk = ~clk ;
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
h_addr <= 11'b0;
end
else if((cnt_h_addr >= H_DATA_STA - 1) &&(cnt_h_addr <= H_DATA_STO - 1))begin
h_addr <= cnt_h_addr - H_DATA_STA;
end
else begin
h_addr <= 11'd0;
end
end
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
v_addr <= 11'b0;
end
else if((cnt_v_addr >= V_DATA_STA - 1) && (cnt_v_addr <= V_DATA_STO - 1))begin
v_addr <= cnt_v_addr - V_DATA_STA;
end
else begin
v_addr <= 11'd0;
end
end
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
vga_r <= 8'd0;
vga_g <= 8'd0;
vga_b <= 8'd0;
vga_blk <= 1'b0;
end
else if((cnt_h_addr >= H_DATA_STA - 1) && (cnt_h_addr <= H_DATA_STO - 1)
&& (cnt_v_addr >= V_DATA_STA - 1) && (cnt_v_addr <= V_DATA_STO - 1)) begin
vga_r <= data_dis[23:16];
vga_g <= data_dis[15:8] ;
vga_b <= data_dis[7:0] ;
vga_blk <= 1'b1 ;
end
else begin
vga_r <= 8'd0;
vga_g <= 8'd0;
vga_b <= 8'd0;
vga_blk <= 1'b0;
end
end
endmodule
data_gen则是vga显示的数据生成文件
代码：
module data_gen (
input clk ,
input rst_n ,
input [10:0] h_addr , //数据有效显示区域行地址
input [10:0] v_addr , //数据有效显示区域场地址
output reg [23:0] data_dis
);
//参数定义
parameter BLACK = 24'h000_000 ,
RED = 24'hFF0_000 ,
GREEN = 24'h00F_F00 ,
BLUE = 24'h000_0FF ,
YELLOW = 24'hFFF_F00 ,
SKY_BULE= 24'h00F_FFF ,
PURPLE = 24'hFF0_0FF ,
GRAY = 24'hC0C_0C0 ,
WHITE = 24'hFFF_FFF ;
always @(posedge clk or negedge rst_n) begin
if(!rst_n)begin
data_dis <= WHITE;
end
else begin
case (h_addr)
0 : data_dis <= BLACK ;
100 : data_dis <= RED ;
200: data_dis <= GREEN ;
300: data_dis <= BLUE ;
400: data_dis <= YELLOW ;
500: data_dis <= SKY_BULE;
600: data_dis <= PURPLE ;
700: data_dis <= GRAY ;
default:data_dis<=data_dis;
endcase
end
end
endmodule
顶层文件：
module vga_top (
input clk ,
input rst_n ,
output wire hsync ,
output wire vsync ,
output wire [7:0] vga_r ,
output wire [7:0] vga_g ,
output wire [7:0] vga_b ,
output wire vga_blk ,
output wire vga_clk
);
wire [23:0] data_dis ;
wire [10:0] h_addr ;
wire [10:0] v_addr ;
data_gen u_data_gen(
.clk (clk ) ,
.rst_n (rst_n ) ,
.h_addr (h_addr ) , //数据有效显示区域行地址
.v_addr (v_addr ) , //数据有效显示区域场地址
.data_dis (data_dis)
);
vga_ctrl u_vga_ctrl(
.clk (clk ) ,
.rst_n (rst_n ) ,
.data_dis (data_dis) ,
.h_addr (h_addr ) , //数据有效显示区域行地址
.v_addr (v_addr ) , //数据有效显示区域场地址
.hsync (hsync ) ,
.vsync (vsync ) ,
.vga_r (vga_r ) ,
.vga_g (vga_g ) ,
.vga_b (vga_b ) ,
.vga_blk (vga_blk ) ,
.vga_clk (vga_clk )
);
endmodule
3.实现效果
二、显示自定义的汉字字符
1.字模提取
下载PCtoLCD取字模
设置字宽字高
输入提取字模的字
选择另存为bmp
打开刚才保存的bmp文件
点击生成字模并保存字模
格式选择c51
这就是需要的字模数据
2.代码
module VGA_test(
OSC_50, //原CLK2_50时钟信号
VGA_CLK, //VGA自时钟
VGA_HS, //行同步信号
VGA_VS, //场同步信号
VGA_BLANK, //复合空白信号控制信号 当BLANK为低电平时模拟视频输出消隐电平，此时从R9~R0,G9~G0,B9~B0输入的所有数据被忽略
VGA_SYNC, //符合同步控制信号 行时序和场时序都要产生同步脉冲
VGA_R, //VGA绿色
VGA_B, //VGA蓝色
VGA_G); //VGA绿色
input OSC_50; //外部时钟信号CLK2_50
output VGA_CLK,VGA_HS,VGA_VS,VGA_BLANK,VGA_SYNC;
output [7:0] VGA_R,VGA_B,VGA_G;
parameter H_FRONT = 16; //行同步前沿信号周期长
parameter H_SYNC = 96; //行同步信号周期长
parameter H_BACK = 48; //行同步后沿信号周期长
parameter H_ACT = 640; //行显示周期长
parameter H_BLANK = H_FRONT+H_SYNC+H_BACK; //行空白信号总周期长
parameter H_TOTAL = H_FRONT+H_SYNC+H_BACK+H_ACT; //行总周期长耗时
parameter V_FRONT = 11; //场同步前沿信号周期长
parameter V_SYNC = 2; //场同步信号周期长
parameter V_BACK = 31; //场同步后沿信号周期长
parameter V_ACT = 480; //场显示周期长
parameter V_BLANK = V_FRONT+V_SYNC+V_BACK; //场空白信号总周期长
parameter V_TOTAL = V_FRONT+V_SYNC+V_BACK+V_ACT; //场总周期长耗时
reg [10:0] H_Cont; //行周期计数器
reg [10:0] V_Cont; //场周期计数器
wire [7:0] VGA_R; //VGA红色控制线
wire [7:0] VGA_G; //VGA绿色控制线
wire [7:0] VGA_B; //VGA蓝色控制线
reg VGA_HS;
reg VGA_VS;
reg [10:0] X; //当前行第几个像素点
reg [10:0] Y; //当前场第几行
reg CLK_25;
always@(posedge OSC_50)
begin
CLK_25=~CLK_25; //时钟
end
assign VGA_SYNC = 1'b0; //同步信号低电平
assign VGA_BLANK = ~((H_Cont<H_BLANK)||(V_Cont<V_BLANK)); //当行计数器小于行空白总长或场计数器小于场空白总长时，空白信号低电平
assign VGA_CLK = ~CLK_to_DAC; //VGA时钟等于CLK_25取反
assign CLK_to_DAC = CLK_25;
always@(posedge CLK_to_DAC)
begin
if(H_Cont<H_TOTAL) //如果行计数器小于行总时长
H_Cont<=H_Cont+1'b1; //行计数器+1
else H_Cont<=0; //否则行计数器清零
if(H_Cont==H_FRONT-1) //如果行计数器等于行前沿空白时间-1
VGA_HS<=1'b0; //行同步信号置0
if(H_Cont==H_FRONT+H_SYNC-1) //如果行计数器等于行前沿+行同步-1
VGA_HS<=1'b1; //行同步信号置1
if(H_Cont>=H_BLANK) //如果行计数器大于等于行空白总时长
X<=H_Cont-H_BLANK; //X等于行计数器-行空白总时长 （X为当前行第几个像素点）
else X<=0; //否则X为0
end
always@(posedge VGA_HS)
begin
if(V_Cont<V_TOTAL) //如果场计数器小于行总时长
V_Cont<=V_Cont+1'b1; //场计数器+1
else V_Cont<=0; //否则场计数器清零
if(V_Cont==V_FRONT-1) //如果场计数器等于场前沿空白时间-1
VGA_VS<=1'b0; //场同步信号置0
if(V_Cont==V_FRONT+V_SYNC-1) //如果场计数器等于行前沿+场同步-1
VGA_VS<=1'b1; //场同步信号置1
if(V_Cont>=V_BLANK) //如果场计数器大于等于场空白总时长
Y<=V_Cont-V_BLANK; //Y等于场计数器-场空白总时长 （Y为当前场第几行）
else Y<=0; //否则Y为0
end
reg valid_yr;
always@(posedge CLK_to_DAC)
if(V_Cont == 10'd32) //场计数器=32时
valid_yr<=1'b1; //行输入激活
else if(V_Cont==10'd512) //场计数器=512时
valid_yr<=1'b0; //行输入冻结
wire valid_y=valid_yr; //连线
reg valid_r;
always@(posedge CLK_to_DAC)
if((H_Cont == 10'd32)&&valid_y) //行计数器=32时
valid_r<=1'b1; //像素输入激活
else if((H_Cont==10'd512)&&valid_y) //行计数器=512时
valid_r<=1'b0; //像素输入冻结
wire valid = valid_r; //连线
wire[10:0] x_dis; //像素显示控制信号
wire[10:0] y_dis; //行显示控制信号
assign x_dis=X; //连线X
assign y_dis=Y; //连线Y
parameter //点阵字模：每一行char_lineXX是显示的一行，共304列
char_line00=256'h0000000000000000000000000000000000000000000000000000000000000000, //第1行
char_line01=256'h0000000000000000000000000000000000000000000000000000000000000000, //第2行
char_line02=256'h0001000000800200000020000000000000000000000000000000000000000000, //第3行
char_line03=256'h0001803000C0030000C070000000000000000000000000000000000000000000, //第4行
char_line04=256'h0C01002000C5030000E060000000000000000000000000000000000000000000, //第5行
char_line05=256'h071220203FFE86000180C0000000000000000000000000000000000000000000, //第6行
char_line06=256'h031FF02000C0D600018181000000000000000000000001E003C00FFC07E001E0, //第7行
char_line07=256'h0318302000C0D7FC018300C000000000000000000000061806200FFC08380618, //第8行
char_line08=256'h0018302000C8AC1803060060000000000000000000000C180C30100010180C18, //第9行
char_line09=256'h001830240FFC2A10031FFFF000000000000000000000081818181000200C0818, //第10行
char_line0a=256'h001FFFFC00002BA0060F003000000000000000000000180018181000200C1800, //第11行
char_line0b=256'h02183020100053000701001000000000000000000000100018081000300C1000, //第12行
char_line0c=256'h7F1830201FFF43000F018380000000000000000000001000300C1000300C1000, //第13行
char_line0d=256'h061830203007C2800B0300E0000000000000000000003000300C1000000C3000, //第14行
char_line0e=256'h061FF0203024C6801B0640700000000000000000000033E0300C13E0001833E0, //第15行
char_line0f=256'h061834206FF8C640130CE018000000000000000000003630300C143000183630, //第16行
char_line10=256'h061836200000CC402310C098000000000000000000003818300C181800303818, //第17行
char_line11=256'h061833200000C8604321FFC0000000000000000000003808300C100800603808, //第18行
char_line12=256'h061833200FF818300303018000000000000000000000300C300C000C00C0300C, //第19行
char_line13=256'h067FF3200C18201C0303018000000000000000000000300C300C000C0180300C, //第20行
char_line14=256'h0600F0200C18C0080304830000000000000000000000300C300C000C0300300C, //第21行
char_line15=256'h0601B0200FF906000308820000000000000000000000300C300C000C0200300C, //第22行
char_line16=256'h062130200C101B000310460000000000000000000000300C1808300C0404300C, //第23行
char_line17=256'h06C330200020191003202C0000000000000000000000180C1818300C0804180C, //第24行
char_line18=256'h0786302004309908030038000000000000000000000018081818201810041808, //第25行
char_line19=256'h070C30200230980C03001800000000000000000000000C180C302018200C0C18, //第26行
char_line1a=256'h061830200320984403007E00000000000000000000000E30062018303FF80E30, //第27行
char_line1b=256'h02203020024F98440300C7800000000000000000000003E003C007C03FF803E0, //第28行
char_line1c=256'h00C3E3E003F31870030301FC0000000000000000000000000000000000000000, //第29行
char_line1d=256'h0100E0E03E000FE0031C00700000000000000000000000000000000000000000, //第30行
char_line1e=256'h0000404030000000026000100000000000000000000000000000000000000000, //第31行
char_line1f=256'h0000000000000000000000000000000000000000000000000000000000000000; //第32行
reg[8:0] char_bit;
always@(posedge CLK_to_DAC)
if(X==10'd144)char_bit<=9'd272; //当显示到144像素时准备开始输出图像数据
else if(X>10'd144&&X<10'd416) //左边距屏幕144像素到416像素时 416=144+272（图像宽度）
char_bit<=char_bit-1'b1; //倒着输出图像信息
reg[29:0] vga_rgb; //定义颜色缓存
always@(posedge CLK_to_DAC)
if(X>10'd144&&X<10'd416) //X控制图像的横向显示边界：左边距屏幕左边144像素 右边界距屏幕左边界416像素
begin case(Y) //Y控制图像的纵向显示边界：从距离屏幕顶部160像素开始显示第一行数据
10'd160:
if(char_line00[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000; //如果该行有数据 则颜色为红色
else vga_rgb<=30'b0000000000_0000000000_0000000000; //否则为黑色
10'd162:
if(char_line01[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd163:
if(char_line02[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd164:
if(char_line03[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd165:
if(char_line04[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd166:
if(char_line05[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd167:
if(char_line06[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd168:
if(char_line07[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd169:
if(char_line08[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd170:
if(char_line09[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd171:
if(char_line0a[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd172:
if(char_line0b[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd173:
if(char_line0c[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd174:
if(char_line0d[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd175:
if(char_line0e[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd176:
if(char_line0f[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd177:
if(char_line10[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd178:
if(char_line11[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd179:
if(char_line12[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd180:
if(char_line13[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd181:
if(char_line14[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd182:
if(char_line15[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd183:
if(char_line16[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd184:
if(char_line17[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd185:
if(char_line18[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd186:
if(char_line19[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd187:
if(char_line1a[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd188:
if(char_line1b[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd189:
if(char_line1c[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd190:
if(char_line1d[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd191:
if(char_line1e[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
10'd192:
if(char_line1f[char_bit])vga_rgb<=30'b1111111111_0000000000_0000000000;
else vga_rgb<=30'b0000000000_0000000000_0000000000;
default:vga_rgb<=30'h0000000000; //默认颜色黑色
endcase
end
else vga_rgb<=30'h000000000; //否则黑色
assign VGA_R=vga_rgb[23:16];
assign VGA_G=vga_rgb[15:8];
assign VGA_B=vga_rgb[7:0];
endmodule
3.实现效果
三、输出一幅彩色图像
1.图像转换
选择一张图片用画图打开
重设大小，我的这张图是400*343
另存为bmp
打开位图转换工具，生成mif文件
2.IP核调用
搜索ip核rom
选择后
de2-115的vga是24位，所以bits选择24
大小为400*343
选中mif文件finish
实例化
3.代码
vga驱动
module vga_drive (input wire clk,
input wire rst_n,
input wire [ 23:0 ] rgb_data,
output wire vga_clk,
output reg h_sync,
output reg v_sync,
output reg [ 11:0 ] addr_h,
output reg [ 11:0 ] addr_v,
output wire [ 7:0 ] rgb_r,
output wire [ 7:0 ] rgb_g,
output wire [ 7:0 ] rgb_b
);
// 640 * 480 60HZ
localparam H_FRONT = 16;
localparam H_SYNC = 96;
localparam H_BLACK = 48;
localparam H_ACT = 640;
localparam V_FRONT = 11;
localparam V_SYNC = 2;
localparam V_BLACK = 31;
localparam V_ACT = 480;
localparam H_TOTAL = H_FRONT + H_SYNC + H_BLACK + H_ACT; // 行周期
localparam V_TOTAL = V_FRONT + V_SYNC + V_BLACK + V_ACT; // 列周期
reg [ 11:0 ] cnt_h ; // 行计数器
reg [ 11:0 ] cnt_v ; // 场计数器
reg [ 23:0 ] rgb ; // 对应显示颜色值
// 对应计数器开始、结束、计数信号
wire flag_enable_cnt_h ;
wire flag_clear_cnt_h ;
wire flag_enable_cnt_v ;
wire flag_clear_cnt_v ;
wire flag_add_cnt_v ;
wire valid_area ;
wire clk_25 ;
wire clk_50 ;
//PLL
pll_one pll_one_inst (
.areset ( ~rst_n ),
.inclk0 ( clk ),
.c0 ( clk_50 ), //50M
.c1 ( clk_25 ) //25M
);
//根据不同分配率选择不同频率时钟
assign vga_clk = clk_25;
// 行计数
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
cnt_h <= 0;
end
else if ( flag_enable_cnt_h ) begin
if ( flag_clear_cnt_h ) begin
cnt_h <= 0;
end
else begin
cnt_h <= cnt_h + 1;
end
end
else begin
cnt_h <= 0;
end
end
assign flag_enable_cnt_h = 1;
assign flag_clear_cnt_h = cnt_h == H_TOTAL - 1;
// 行同步信号
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
h_sync <= 0;
end
else if ( cnt_h == H_SYNC - 1 ) begin // 同步周期时为1
h_sync <= 1;
end
else if ( flag_clear_cnt_h ) begin // 其余为0
h_sync <= 0;
end
else begin
h_sync <= h_sync;
end
end
// 场计数
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
cnt_v <= 0;
end
else if ( flag_enable_cnt_v ) begin
if ( flag_clear_cnt_v ) begin
cnt_v <= 0;
end
else if ( flag_add_cnt_v ) begin
cnt_v <= cnt_v + 1;
end
else begin
cnt_v <= cnt_v;
end
end
else begin
cnt_v <= 0;
end
end
assign flag_enable_cnt_v = flag_enable_cnt_h;
assign flag_clear_cnt_v = cnt_v == V_TOTAL - 1;
assign flag_add_cnt_v = flag_clear_cnt_h;
// 场同步信号
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
v_sync <= 0;
end
else if ( cnt_v == V_SYNC - 1 ) begin
v_sync <= 1;
end
else if ( flag_clear_cnt_v ) begin
v_sync <= 0;
end
else begin
v_sync <= v_sync;
end
end
// 对应有效区域行地址 1-640
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
addr_h <= 0;
end
else if ( valid_area ) begin
addr_h <= cnt_h - H_SYNC - H_BLACK + 1;
end
else begin
addr_h <= 0;
end
end
// 对应有效区域列地址 1-480
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
addr_v <= 0;
end
else if ( valid_area ) begin
addr_v <= cnt_v -V_SYNC - V_BLACK + 1;
end
else begin
addr_v <= 0;
end
end
// 有效显示区域
assign valid_area = cnt_h >= H_SYNC + H_BLACK && cnt_h <= H_SYNC + H_BLACK + H_ACT && cnt_v >= V_SYNC + V_BLACK && cnt_v <= V_SYNC + V_BLACK + V_ACT;
// 显示颜色
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
rgb <= 24'h0;
end
else if ( valid_area ) begin
rgb <= rgb_data;
end
else begin
rgb <= 24'b0;
end
end
assign rgb_r = rgb[ 23:16 ];
assign rgb_g = rgb[ 15:8 ];
assign rgb_b = rgb[ 7:0 ];
endmodule // vga_dirve
数据转rgb
module data_drive (input wire vga_clk,
input wire rst_n,
input wire [ 11:0 ] addr_h,
input wire [ 11:0 ] addr_v,
output reg [ 23:0 ] rgb_data);
parameter height = 343; // 图片高度
parameter width = 400; // 图片宽度
reg [ 17:0 ] rom_address ; // ROM地址
wire [ 23:0 ] rom_data ; // 图片数据
wire flag_clear_rom_address ; // 地址清零
wire flag_begin_h ; // 图片显示行
wire flag_begin_v ; // 图片显示列
wire flag_enable_out ;
//状态输出
always @( * ) begin
if (flag_enable_out) begin
rgb_data = rom_data;
end
else begin
rgb_data= 0;
end
end
assign flag_begin_h = addr_h > ( ( 640 - width ) / 2 ) && addr_h < ( ( 640 - width ) / 2 ) + width + 1;
assign flag_begin_v = addr_v > ( ( 480 - height )/2 ) && addr_v <( ( 480 - height )/2 ) + height + 1;
assign flag_enable_out = flag_begin_h && flag_begin_v;
//ROM地址计数器
always @( posedge vga_clk or negedge rst_n ) begin
if ( !rst_n ) begin
rom_address <= 0;
end
else if ( flag_clear_rom_address ) begin //计数满清零
rom_address <= 0;
end
else if ( flag_enable_out ) begin //在有效区域内+1
rom_address <= rom_address + 1;
end
else begin //无效区域保持
rom_address <= rom_address;
end
end
assign flag_clear_rom_address = rom_address == height * width - 1;
//实例化ROM
rom_2 rom_one_inst (
.address ( rom_address ),
.clock ( vga_clk ),
.q ( rom_data )
);
endmodule // data_drive
顶层文件
module vga_top (input wire clk,
input wire rst_n,
output wire vga_clk,
output wire h_sync,
output wire v_sync,
output wire [ 7:0 ] rgb_r,
output wire [ 7:0 ] rgb_g,
output wire [ 7:0 ] rgb_b
);
reg [ 27:0 ] cnt ;
wire [ 11:0 ] addr_h ;
wire [ 11:0 ] addr_v ;
wire [ 23:0 ] rgb_data ;
//vga模块
vga_drive u_vga_drive(
.clk ( clk ),
.rst_n ( rst_n ),
.rgb_data ( rgb_data ),
.vga_clk ( vga_clk ),
.h_sync ( h_sync ),
.v_sync ( v_sync ),
.rgb_r ( rgb_r ),
.rgb_g ( rgb_g ),
.rgb_b ( rgb_b ),
.addr_h ( addr_h ),
.addr_v ( addr_v )
);
//数据模块
data_drive u_data_drive(
.vga_clk ( vga_clk ),
.rst_n ( rst_n ),
.addr_h ( addr_h ),
.addr_v ( addr_v ),
.rgb_data ( rgb_data )
);
endmodule // vga_top
4.实现效果
四、参考
https://blog.youkuaiyun.com/qq_47281915/article/details/125134764?spm=1001.2014.3001.5502
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