quadrature.v

xilinx fpga 做VGA驱动信号的Verilog原代码,ise版本9.2

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: 
// 
// Create Date:    00:04:40 05/30/2008 
// Design Name: 
// Module Name:    quadrature 
// Project Name: 
// Target Devices: 
// Tool versions: 
// Description: 
//
// Dependencies: 
//
// Revision: 
// Revision 0.01 - File Created
// Additional Comments: 
//
//////////////////////////////////////////////////////////////////////////////////
module quadrature();
reg [8:0] PaddlePosition;
reg [2:0] quadAr, quadBr;
always @(posedge clk) quadAr <= {quadAr[1:0], quadA};
always @(posedge clk) quadBr <= {quadBr[1:0], quadB};

always @(posedge clk)
if(quadAr[2] ^ quadAr[1] ^ quadBr[2] ^ quadBr[1])
begin
  if(quadAr[2] ^ quadBr[1])
  begin
    if(~&PaddlePosition)        // make sure the value doesn't overflow
      PaddlePosition <= PaddlePosition + 1;
  end 
  else
  begin
    if(|PaddlePosition)        // make sure the value doesn't underflow
      PaddlePosition <= PaddlePosition - 1;
  end
end 

wire border = (CounterX[9:3]==0) || (CounterX[9:3]==79) || (CounterY[8:3]==0) || (CounterY[8:3]==59);
wire paddle = (CounterX>=PaddlePosition+8) && (CounterX<=PaddlePosition+120) && (CounterY[8:4]==27);

wire R = border | (CounterX[3] ^ CounterY[3]) | paddle;
wire G = border | paddle;
wire B = border | paddle; 
reg [9:0] ballX;
reg [8:0] ballY;
reg ball_inX, ball_inY;

always @(posedge clk)
if(ball_inX==0) ball_inX <= (CounterX==ballX) & ball_inY; else ball_inX <= !(CounterX==ballX+16);

always @(posedge clk)
if(ball_inY==0) ball_inY <= (CounterY==ballY); else ball_inY <= !(CounterY==ballY+16);

wire ball = ball_inX & ball_inY; 
wire border = (CounterX[9:3]==0) || (CounterX[9:3]==79) || (CounterY[8:3]==0) || (CounterY[8:3]==59);
wire paddle = (CounterX>=PaddlePosition+8) && (CounterX<=PaddlePosition+120) && (CounterY[8:4]==27);
wire BouncingObject = border | paddle; // active if the border or paddle is redrawing itself

reg CollisionX1, CollisionX2, CollisionY1, CollisionY2;
always @(posedge clk) if(BouncingObject & (CounterX==ballX ) & (CounterY==ballY+ 8)) CollisionX1<=1;
always @(posedge clk) if(BouncingObject & (CounterX==ballX+16) & (CounterY==ballY+ 8)) CollisionX2<=1;
always @(posedge clk) if(BouncingObject & (CounterX==ballX+ 8) & (CounterY==ballY )) CollisionY1<=1;
always @(posedge clk) if(BouncingObject & (CounterX==ballX+ 8) & (CounterY==ballY+16)) CollisionY2<=1; 
reg UpdateBallPosition;
always @(posedge clk) UpdateBallPosition <= (CounterY==500) & (CounterX==0); // active only once for every video frame

reg ball_dirX, ball_dirY;
always @(posedge clk)
if(UpdateBallPosition)
begin
  if(~(CollisionX1 & CollisionX2))        // if collision on both X-sides, don't move in the X direction
  begin
    ballX <= ballX + (ball_dirX ? -1 : 1);
    if(CollisionX2) ball_dirX <= 1; else if(CollisionX1) ball_dirX <= 0;
  end

  if(~(CollisionY1 & CollisionY2))        // if collision on both Y-sides, don't move in the Y direction
  begin
    ballY <= ballY + (ball_dirY ? -1 : 1);
    if(CollisionY2) ball_dirY <= 1; else if(CollisionY1) ball_dirY <= 0;
  end
end 
wire R = BouncingObject | ball | (CounterX[3] ^ CounterY[3]);
wire G = BouncingObject | ball;
wire B = BouncingObject | ball;

reg vga_R, vga_G, vga_B;
always @(posedge clk)
begin
  vga_R <= R & inDisplayArea;
  vga_G <= G & inDisplayArea;
  vga_B <= B & inDisplayArea;
end 


endmodule