今天首先了解到了昨天不太清楚的一些名词的含义以及使用方法，也明白了分辨率，帧率的含义
其次学习了在vga上显示256种颜色代码
代码思路上和上一篇文章挺像的，只是加之在有效区之上划分出来了256个小格子，并在各个小格子上利用不同的rgb值赋予不同的颜色，有区别的是，上一篇文章中的rgb三个输出端口都是一位的，而这次分别是三位，三位，二位。
令我不太理解的一点是，上一篇文章的制作是以800*600的分辨率制作的，而这次的分辨率是640*480，各个数据都会有所变化，而现在就我的电脑而言，有许多种的分辨率选择，所以接下来我要着手尝试一下上述功能，附代码：
module vga_2( input clk_25m, input rst_n, output hsync, output vsync, output [2:0]vga_r,// 8位rgb来配置256色 output [2:0]vga_g, output [1:0]vga_b ); reg [9:0] x_cnt; reg [9:0] y_cnt; always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) x_cnt <= 10'd0; else if(x_cnt == 10'd799) x_cnt <= 10'd0; else x_cnt <= x_cnt + 1'b1; end always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) y_cnt <= 10'd0; else if(y_cnt == 10'd524) y_cnt <= 10'd0; else if(x_cnt == 10'd799) y_cnt <= y_cnt + 1'b1; else y_cnt <= y_cnt; end reg hsync_r,vsync_r; always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) hsync_r <= 1'b1; else if(x_cnt == 10'd0) hsync_r <= 1'b0; else if(x_cnt == 10'd96) hsync_r <= 1'b1; else hsync_r <= hsync_r; end always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) vsync_r <= 1'b1; else if(y_cnt == 10'd0) vsync_r <= 1'b0; else if(y_cnt == 10'd2) vsync_r <= 1'b1; else vsync_r <= vsync_r; end assign hsync = hsync_r; assign vsync = vsync_r; reg valid_yr; always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) valid_yr <= 1'b0; else if(y_cnt == 10'd32) valid_yr <= 1'b1; else if(y_cnt == 10'd512) valid_yr <= 1'b0; else valid_yr <= valid_yr; end wire valid_y = valid_yr; reg valid_r; always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) valid_r <= 1'b0; else if( (x_cnt == 10'd141) && valid_y ) valid_r <= 1'b1; else if( (x_cnt == 10'd781) && valid_y ) valid_r <= 1'b0; else valid_r <= valid_r; end wire valid = valid_r; wire [9:0] x_dis; // 横坐标显示有效区域相对坐标值0-639 wire [9:0] y_dis; // 数坐标显示有效区域相对坐标值0-479 assign x_dis = x_cnt - 10'd142; assign y_dis = y_cnt - 10'd33; reg [7:0] vga_rgb; // vga色彩显示寄存器 always@(posedge clk_25m ) begin if(!valid) vga_rgb <= 8'd0; else begin case(x_dis) 10'd0: begin if(y_dis >= 10'd0 && y_dis < 10'd30) vga_rgb <= 8'd0; else if(y_dis >= 10'd30 && y_dis < 10'd60) vga_rgb <= 8'd16; else if(y_dis >= 10'd60 && y_dis < 10'd90) vga_rgb <= 8'd32; else if(y_dis >= 10'd90 && y_dis < 10'd120) vga_rgb <= 8'd48; else if(y_dis >= 10'd120 && y_dis < 10'd150) vga_rgb <= 8'd64; else if(y_dis >= 10'd150 && y_dis < 10'd180) vga_rgb <= 8'd80; else if(y_dis >= 10'd180 && y_dis < 10'd210) vga_rgb <= 8'd96; else if(y_dis >= 10'd210 && y_dis < 10'd240) vga_rgb <= 8'd112; else if(y_dis >= 10'd240 && y_dis < 10'd270) vga_rgb <= 8'd128; else if(y_dis >= 10'd270 && y_dis < 10'd300) vga_rgb <= 8'd144; else if(y_dis >= 10'd300 && y_dis < 10'd330) vga_rgb <= 8'd160; else if(y_dis >= 10'd330 && y_dis < 10'd360) vga_rgb <= 8'd176; else if(y_dis >= 10'd360 && y_dis < 10'd390) vga_rgb <= 8'd192; else if(y_dis >= 10'd390 && y_dis < 10'd420) vga_rgb <= 8'd208; else if(y_dis >= 10'd420 && y_dis < 10'd450) vga_rgb <= 8'd224; else vga_rgb <= 8'd240; end 10'd40,10'd80,10'd120, 10'd160,10'd200,10'd240, 10'd280,10'd320,10'd360, 10'd400,10'd440,10'd480, 10'd520,10'd560,10'd600,10'd640: vga_rgb <= vga_rgb + 1'b1; default: ; endcase end endassign vga_r = vga_rgb[7:5];assign vga_g = vga_rgb[4:2];assign vga_b = vga_rgb[1:0]; endmodule
转载于:https://www.cnblogs.com/fpgamzy/p/10343949.html
