www.pudn.com > vga_colors.rar > vga_sync.v, change:2009-03-09,size:5392b

/* 
 *  Copyright (C) 2006-2008 CMM Sigma Andrzej Chmielowiec <cmmsigma@cmmsigma.eu> 
 * 
 *  This program is free software; you can redistribute it and/or modify 
 *  it under the terms of the GNU General Public License version 3 
 *  as published by the Free Software Foundation. 
 * 
 *  This program is distributed in the hope that it will be useful, 
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of 
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 *  GNU General Public License for more details. 
 * 
 *  If you want to use this code under other conditions, please contact  
 *  CMM Sigma <cmmsigma@cmmsigma.eu>. 
 */ 
 
/* 
 * This module contains logic functions which are needed  
 * to send signals during VGA interface. 
 * 
 * Module paramters 
 * ================ 
 * 
 * H_PIXELS -  
 *   Number of pixels in horizontal mode. 
 * 
 * H_FRONT -  
 *   Number of pixels before horizontal synchronization  
 *   signal. 
 * 
 * H_SYNC -  
 *   Number of pixels during horizontal synchronization  
 *   signal. 
 * 
 * H_BACK -  
 *   Number of pixels after horizontal synchronization  
 *   signal. 
 * 
 * V_LINES -  
 *   Number of lines in vertical mode. 
 * 
 * V_FRONT -  
 *   Number of lines before vertical synchronization  
 *   signal. 
 * 
 * V_SYNC -  
 *   Number of lines during vertical synchronization  
 *   signal. 
 * 
 * V_BACK -  
 *   Number of lines after vertical synchronization  
 *   signal. 
 * 
 * 
 * Module signals 
 * ============== 
 * 
 * hSync[out] -  
 *   Horizontal synchronization of VGA display. 
 * 
 * vSync[out] - 
 *   Vertical synchronization of VGA display. 
 * 
 * redOut[out] - 
 *   Red color component for given pixel. 
 * 
 * greenOut[out] -  
 *   Green color component for given pixel. 
 * 
 * blueOut[out] -  
 *   Blue color component for given pixel. 
 * 
 * pixel[out] -  
 *   Number of pixel which is actualy displayed (pixels   
 *   are numbered from 0 from left side of the screen). 
 * 
 * line[out] - 
 *   Number of line which is actualy displayed (lines are  
 *   numbered from 0 from top of the screen). 
 * 
 * redIn[in] -  
 *   Red color component for given pixel. If pixel is  
 *   invisible, then this signal is ignored and redOut  
 *   is 1'b0. 
 * 
 * greenIn[in] -  
 *   Green color component for given pixel. If pixel is  
 *   invisible, then this signal is ignored and greenOut  
 *   is 1'b0. 
 * 
 * blueIn[in] -  
 *   Blue color component for given pixel. If pixel is  
 *   invisible, then this signal is ignored and blueOut  
 *   is 1'b0. 
 * 
 * clk[in] -  
 *   Clock signal adequate for pixel density (25.175 for  
 *   640x480 at 60Hz). 
 */ 
module VgaSync # 
( 
	parameter H_PIXELS = 640, 
	parameter H_FRONT = 16, 
	parameter H_SYNC = 96, 
	parameter H_BACK = 48, 
	parameter H_SYNC_VALUE = 1'b0, 
	parameter V_LINES = 480, 
	parameter V_FRONT = 10, 
	parameter V_SYNC = 2, 
	parameter V_BACK = 33, 
	parameter V_SYNC_VALUE = 1'b0 
) 
( 
	output reg hSync, 
	output reg vSync, 
	output reg redOut, 
	output reg greenOut, 
	output reg blueOut, 
	output reg [11:0] pixel, 
	output reg [11:0] line, 
	input redIn, 
	input greenIn, 
	input blueIn, 
	input clk 
); 
 
	`define H_A (H_PIXELS) 
	`define H_B (`H_A + H_FRONT) 
	`define H_C (`H_B + H_SYNC) 
	`define H_D (`H_C + H_BACK) 
 
	`define V_A (V_LINES) 
	`define V_B (`V_A + V_FRONT) 
	`define V_C (`V_B + V_SYNC) 
	`define V_D (`V_C + V_BACK) 
 
	reg signal = 1'b1; 
 
	/* 
	 *   DDDDDDDDD...DDDDDDDDDDDDDDDDDDDDD-----HHH----- 
	 *   DDDDDDDDD...DDDDDDDDDDDDDDDDDDDDD-----HHH----- 
	 *   DDDDDDDDD...DDDDDDDDDDDDDDDDDDDDD-----HHH----- 
	 *             .                            . 
	 *             .                            . 
	 *             .                            . 
	 *   DDDDDDDDD...DDDDDDDDDDDDDDDDDDDDD-----HHH----- 
	 *   DDDDDDDDD...DDDDDDDDDDDDDDDDDDDDD-----HHH----- 
	 *   --------------------------------------HHH----- 
	 *   --------------------------------------HHH----- 
	 *   VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVXXXVVVVV 
	 *   VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVXXXVVVVV 
	 *   --------------------------------------HHH----- 
	 *   --------------------------------------HHH----- 
	 * 
	 * D - video is displayed. 
	 * H - only horizontal synchronization. 
	 * V - only vertical synchronization. 
	 * X - both horizontal and vertical synchronization. 
	 * 
	 */ 
 
 
	always @(posedge clk) begin 
 
		if (pixel == `H_D - 1) begin 
			if (line  `V_A) begin 
				signal = 1; 
				line = line + 1'b1; 
			end 
			else if (line == `V_B - 1) begin 
				vSync = V_SYNC_VALUE; 
				line = line + 1'b1; 
			end 
			else if (line == `V_C - 1) begin 
				vSync = ~V_SYNC_VALUE; 
				line = line + 1'b1; 
			end 
			else if (line == `V_D - 1) begin 
				line = 0; 
			end 
			else begin 
				line = line + 1'b1; 
			end 
 
			pixel = 0; 
		end 
		else if (pixel == `H_A - 1) begin 
			signal = 0; 
			redOut = 0; 
			greenOut = 0; 
			blueOut = 0; 
			pixel = pixel + 1'b1; 
		end 
		else if (pixel == `H_B - 1) begin 
			hSync = H_SYNC_VALUE; 
			pixel = pixel + 1'b1; 
		end 
		else if (pixel == `H_C - 1) begin 
			hSync = ~H_SYNC_VALUE; 
			pixel = pixel + 1'b1; 
		end 
		else if (signal == 1) begin 
			redOut = redIn; 
			greenOut = greenIn; 
			blueOut = blueIn; 
			pixel = pixel + 1'b1; 
		end 
		else begin 
			pixel = pixel + 10'b1; 
		end 
 
	end 
 
endmodule