这一次的学习任务主要为在vga显示屏上面显示汉字或是字母，代码的原理出现了新的知识，首先汉字或是字母在屏幕上的排列方式转化为代码使用了pctolcd2002软件来完成，在校对好对应的参数之后，就可以通过软件直接来输出代码
例如上述汉字“嘻嘻嘻”，借助软件转化为了我们需要使用的代码
嘻(0) 嘻(1) 嘻(2)
DB 00H 40H;DB 07H FCH;DB F0H 40H;DB 93H F8H;DB 90H 00H;DB 93H F8H;DB 92H 08H;DB 93H F8H;DB 91H 10H;DB 9FH FEH;DB F0H 00H;DB 93H F8H;DB 02H 08H;DB 02H 08H;DB 03H F8H;DB 02H 08H;"嘻",0
DB 00H 40H;DB 07H FCH;DB F0H 40H;DB 93H F8H;DB 90H 00H;DB 93H F8H;DB 92H 08H;DB 93H F8H;DB 91H 10H;DB 9FH FEH;DB F0H 00H;DB 93H F8H;DB 02H 08H;DB 02H 08H;DB 03H F8H;DB 02H 08H;"嘻",1
DB 00H 40H;DB 07H FCH;DB F0H 40H;DB 93H F8H;DB 90H 00H;DB 93H F8H;DB 92H 08H;DB 93H F8H;DB 91H 10H;DB 9FH FEH;DB F0H 00H;DB 93H F8H;DB 02H 08H;DB 02H 08H;DB 03H F8H;DB 02H 08H;"嘻",2
之后就只需要根据vga的扫描方式来完成显示即可，值得一提的是，汉字或是字母等等再vga上的显示过程并不是一个一个完整的，有先后的显示，而是逐行显示，根据之前学到的编辑方式，总体的设计并没有出现什么难题
代码：
module vga_3(
input clk_100mhz, //25mhz input rst_n, output hsync, output vsync, output [2:0]vga_r, output [2:0]vga_g, output [1:0]vga_b );
wire clk_25m; c100_25 u3( .clk_100mhz(clk_100mhz), .rst_n(rst_n), .clk_25m(clk_25m) );
//------------------------------------------------------------------- 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; //------------------------------------------------------------------- parameter char_line0 = 24'h00_00_00, char_line1 = 24'h00_00_00, char_line2 = 24'h00_00_00, char_line3 = 24'hfc_f8_c7, char_line4 = 24'h42_44_62, char_line5 = 24'h48_42_62, char_line6 = 24'h48_42_52, char_line7 = 24'h78_42_52, char_line8 = 24'h48_42_4a, char_line9 = 24'h48_42_4a, char_linea = 24'h40_42_4a, char_lineb = 24'h42_42_46, char_linec = 24'h42_44_46, char_lined = 24'hfc_f8_e2, char_linee = 24'h00_00_00, char_linef = 24'h00_00_00;
reg [4:0]char_bit; // 显示位计算 always@(posedge clk_25m or negedge rst_n) begin if(!rst_n) char_bit <= 5'h1f; else if(x_cnt == 10'd442) char_bit <= 5'd23; else if(x_cnt > 10'd442 && x_cnt < 10'd466) char_bit <= char_bit - 1'b1; else char_bit <= char_bit; end reg [7:0] vga_rgb; // 色彩显示寄存器 always@(posedge clk_25m ) begin if(!valid) vga_rgb <= 8'd0; else if(x_cnt > 10'd442 && x_cnt < 10'd466) begin case(y_dis) 10'd231: if(char_line0[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd232: if(char_line1[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd233: if(char_line2[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd234: if(char_line3[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd235: if(char_line4[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd236: if(char_line5[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd237: if(char_line6[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd238: if(char_line7[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd239: if(char_line8[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd240: if(char_line9[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd241: if(char_linea[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd242: if(char_lineb[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd243: if(char_linec[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd244: if(char_lined[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd245: if(char_linee[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; 10'd246: if(char_linef[char_bit]) vga_rgb <= 8'b111_000_00; else vga_rgb <= 8'b000_111_00; default: vga_rgb <= 8'h00; endcase end else vga_rgb <= 8'h00; end
assign 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/10355462.html
