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2014-2-9 10:11 |
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签到天数: 16 天 连续签到: 1 天 [LV.4]偶尔看看III
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很多开发板都是用IO 去驱动VGA，导致很多用户初次认识VGA是数字信号，其实VGA是模拟信号，最好的图像入门，需要弄清楚基本的图像知识。
本贴提供adv7125的VGA驱动例程，附带简单说明，如有兴趣，可跟帖回复问题。
module vga_control_module
(
VGA_CLK, RSTn,
VGA_X, VGA_Y,
VGA_ACT,
VGA_R, VGA_G, VGA_B
);
input VGA_CLK, RSTn;
input[11:0] VGA_X, VGA_Y;
input VGA_ACT;
output[7:0] VGA_R, VGA_G, VGA_B;
//Pattern Generator
reg[7:0] VGA_Rr, VGA_Gr, VGA_Br;
always @ (posedge VGA_CLK or negedge RSTn)
begin
if (!RSTn)
VGA_Rr <= 0;
else
begin
VGA_Rr <= (VGA_X < 10'd200) ? 8'd255:
// (VGA_Y>=10'd100 && VGA_Y<=10'd200) ? 10'd896:
// (VGA_Y>=10'd200 && VGA_Y<=10'd300) ? 8'd64:
// (VGA_Y>=10'd300 && VGA_Y<=10'd400) ? 8'd128:
// (VGA_Y>=10'd400 && VGA_Y<=10'd500) ? 10'd255:
0;
end
end
always @ (posedge VGA_CLK or negedge RSTn)
begin
if (!RSTn)
VGA_Gr <= 0;
else
begin
VGA_Gr <= (VGA_X>10'd300 && VGA_X < 10'd500) ? 8'd255:
// (VGA_X>=10'd100 && VGA_X<=10'd200) ? 8'd0:
// (VGA_X>=10'd200 && VGA_X<=10'd300) ? 8'd32:
// (VGA_X>=10'd300 && VGA_X<=10'd400) ? 8'd64:
// (VGA_X>=10'd400 && VGA_X<=10'd500) ? 8'd128:
// (VGA_X>=10'd500 && VGA_X<=10'd600) ? 8'd255:
// (VGA_X>=10'd600 && VGA_X<=10'd700) ? 10'd896:
0;
end
end
always @ (posedge VGA_CLK or negedge RSTn)
begin
if (!RSTn)
VGA_Br <= 0;
else
begin
VGA_Br <= (VGA_X>10'd600 && VGA_X < 10'd800) ? 8'd255:
// (VGA_Y>=10'd100 && VGA_Y<=10'd200) ? 8'd255:
// (VGA_Y>=10'd200 && VGA_Y<=10'd300) ? 8'd128:
//(VGA_Y>=10'd300 && VGA_Y<=10'd400) ? 8'd64:
//(VGA_Y>=10'd400 && VGA_Y<=10'd500) ? 8'd32:
0;
end
end
assign VGA_R = VGA_Rr;
assign VGA_G = VGA_Gr;
assign VGA_B = VGA_Br;
endmodule
module sync_module
(
VGA_CLK, RSTn,//VGA_CLK 点频 =H_TOTAL * V_TOTAL *Frame
VGA_HS, VGA_VS,//VGA的行场同步信号
VGA_BLANKn, VGA_SYNCn, //复合消影脉冲与同步电平控制，ADV7125
VGA_X, VGA_Y,// 显示行与场坐标
VGA_ACT,//显示有效区域指示电平
DAC_CLK//点频信号输出，提供给DAC驱动
);
input VGA_CLK, RSTn;
output VGA_HS, VGA_VS;
output VGA_BLANKn, VGA_SYNCn;
output[11:0] VGA_X, VGA_Y; //
output VGA_ACT; // When the VGA is ready to displayy that means in the active area Set to 1
output DAC_CLK;
/**************** 800*600@60HZ ********************//*按照标准时序参考，也可根据具体应用修改部分参数*/
//Horizontal parameter
parameter H_FRONT = 40; // d
parameter H_SYNC = 128; // a
parameter H_BACK = 88; // b
parameter H_ACT = 800; // c
parameter H_BLANK = H_FRONT + H_SYNC + H_BACK;
parameter H_TOTAL = H_BLANK + H_ACT;
//Vertical parameter
parameter V_FRONT = 1; // r
parameter V_SYNC = 4; // o
parameter V_BACK = 23; // p
parameter V_ACT = 600; // q
parameter V_BLANK = V_FRONT + V_SYNC + V_BACK;
parameter V_TOTAL = V_BLANK + V_ACT;
/**************************************************/
//ADV7125
assign DAC_CLK = VGA_CLK;
assign VGA_BLANKn = VGA_HS && VGA_VS;
assign VGA_SYNCn = 1'b0; //If the SOG is not enable, SYNC should be set to 0;
//Horizontal Generator
reg[11:0] H_Count;
reg VGA_HSr;
reg[11:0] VGA_Xr;//X address
reg VGA_HACT; //Horizontal 有效显示区域
always @ (posedge VGA_CLK or negedge RSTn)
begin
if(!RSTn)
begin
VGA_HSr <= 1'b0;
VGA_HACT <= 1'b0;
VGA_Xr <= 12'd0;
H_Count <= 12'd0;
end
else
begin
if (H_Count == H_TOTAL)
H_Count <= 12'd0;
else
H_Count <= H_Count + 1'b1;
// Generate SYNC
if (H_Count <= H_SYNC)
VGA_HSr <= 1'b0;
else
VGA_HSr <= 1'b1;
// Define the active area
if ((H_Count > (H_SYNC+H_BACK))&&(H_Count <= (H_SYNC+H_BACK+H_ACT)))
begin
VGA_HACT <= 1'b1;
VGA_Xr <= H_Count - (H_SYNC+H_BACK+1); // X Address range 0-H_ACT
end
else
begin
VGA_HACT <= 1'b0;
VGA_Xr <= 12'd0;
end
end
end
assign VGA_HS = VGA_HSr;
assign VGA_X = VGA_Xr;
//Vertical Generator
reg[11:0] V_Count;
reg VGA_VSr;
reg[11:0] VGA_Yr;
reg VGA_VACT;
always @ (posedge VGA_CLK or negedge RSTn)
begin
if(!RSTn)
begin
VGA_VSr <= 1'b0;
VGA_VACT <= 1'b0;
VGA_Yr <= 12'd0;
V_Count <= 12'd0;
end
else
begin
if (V_Count == V_TOTAL)
V_Count <= 12'd0;
else if(H_Count == H_TOTAL)
V_Count <= V_Count + 1'b1;
// Generate SYNC
if (V_Count <= V_SYNC)
VGA_VSr <= 1'b0;
else
VGA_VSr <= 1'b1;
// Define the active area
if ((V_Count > (V_SYNC+V_BACK))&&(V_Count <= (V_SYNC+V_BACK+V_ACT)))
begin
VGA_VACT <= 1'b1;
VGA_Yr <= V_Count - (V_SYNC+V_BACK); // Y Address range 0-V_ACT
end
else
begin
VGA_VACT <= 1'b0;
VGA_Yr <= 12'd0;
end
end
end
assign VGA_VS = VGA_VSr;
assign VGA_Y = VGA_Yr;
assign VGA_ACT = VGA_HACT&&VGA_VACT;
endmodule
vga_RGB.rar
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发表于 2014-11-4 16:56:39
发表于 2014-11-4 17:22:37
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