目录
一、设计要求
二、模块总和
三、模块设计
1.顶层模块
2.秒分频模块
3.秒计数模块
4.分钟分频模块
5.分钟计数模块
6.小时分频模块
7.小时计数模块
8.数据分配数码管模块
9.数码管显示模块
10.管脚约束代码
四、引脚分配
1.利用 NEXYS4 DDR 开发板设计一款数字时钟,能够正确显示时、分、秒;
2.数字时钟为24小时进制;

module digital_clock_top(
	input clk,
	input rst_n,
	output  [7:0]sel,
	output  [7:0]seg
);
wire clk_1s;
wire clk_1f;
wire clk_1h;
wire [5:0]cnt_s;
wire [5:0]cnt_f;
wire [4:0]cnt_h;
wire [3:0]bit_s;
wire [3:0]tenbit_s;
wire [3:0]bit_f;
wire [3:0]tenbit_f;
wire [3:0]bit_h;
wire [3:0]tenbit_h;
digital_clock_div_s a(
	.clk(clk),
	.rst_n(rst_n),
	.clk_1s(clk_1s)
    );
digital_clock_count_s b(
	.clk(clk_1s),
	.rst_n(rst_n),
	.cnt_s(cnt_s) 
    );
digital_clock_div_f c(
	.clk(clk),
	.rst_n(rst_n),
	.clk_1f(clk_1f)
    );
digital_clock_count_f d(
	.clk(clk_1f),
	.rst_n(rst_n),
	.cnt_f(cnt_f) 
    );
digital_clock_div_h e(
	.clk(clk),
	.rst_n(rst_n),
	.clk_1h(clk_1h)
    );
digital_clock_count_h f(
	.clk(clk_1h),
	.rst_n(rst_n),
	.cnt_h(cnt_h)
    );
digital_clock_time g(
	.clk(clk),
	.rst_n(rst_n),
	.cnt_s(cnt_s),
	.cnt_f(cnt_f),
	.cnt_h(cnt_h),
	.bit_s(bit_s),
	.tenbit_s(tenbit_s),
	.bit_f(bit_f),
	.tenbit_f(tenbit_f),
	.bit_h(bit_h),
	.tenbit_h(tenbit_h) 
    );
digital_clock_digital h(
	.clk(clk),
	.rst_n(rst_n),
	.bit_s(bit_s),
	.tenbit_s(tenbit_s),
	.bit_f(bit_f),
	.tenbit_f(tenbit_f),
	.bit_h(bit_h),
	.tenbit_h(tenbit_h),
	.sel(sel),
	.seg(seg)
);
endmodule 
module digital_clock_div_s(
	input clk,
	input rst_n,
	output reg clk_1s
    );
//计数器计数1s的数值
reg [25:0]cnt1;
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		cnt1 <= 0;
	else if(cnt1 == 26'd49999999)
		cnt1 <= 0;
	else 
		cnt1 <= cnt1 + 1;
//分频为1s
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		clk_1s <= 0;
	else if(cnt1 == 26'd49999999)
		clk_1s <= ~clk_1s;
	else 
		clk_1s <= clk_1s;
endmodule 
module digital_clock_count_s(
	input clk,
	input rst_n,
	output reg [5:0]cnt_s //计数60秒
    );
	
always @(negedge clk or negedge rst_n)
	if(!rst_n)
		cnt_s <= 0;
	else if(cnt_s == 6'd59) 
		cnt_s <= 0;
	else	 
		cnt_s <= cnt_s + 1;
endmodule 
module digital_clock_div_f(
	input clk,
	input rst_n,
	output reg clk_1f
    );
//计数器计数1分钟的数值
reg [31:0]cnt2;//计数值 ((60000000000/10=6000000000)/2-1)=2,999,999,999
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		cnt2 <= 0;
	else if(cnt2 == 32'd2999999999)
		cnt2 <= 0;
	else 
		cnt2 <= cnt2 + 1;
//分频为1分钟
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		clk_1f <= 0;
	else if(cnt2 == 32'd2999999999)
		clk_1f <= ~clk_1f;
	else 
		clk_1f <= clk_1f;
endmodule 
module digital_clock_count_f(
	input clk,
	input rst_n,
	output reg [5:0]cnt_f //计数60分
    );
	
always @(negedge clk or negedge rst_n)
	if(!rst_n)
		cnt_f <= 0;
	else if(cnt_f == 6'd59) 
		cnt_f <= 0;
	else	 
		cnt_f <= cnt_f + 1;
endmodule 
module digital_clock_div_h(
	input clk,
	input rst_n,
	output reg clk_1h
    );
//计数器计数1小时的数值
reg [37:0]cnt3;//计数值 ((3600000000000/10=360000000000)/2-1)=179,999,999,999
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		cnt3 <= 0;
	else if(cnt3 == 38'd179999999999)
		cnt3 <= 0;
	else 
		cnt3 <= cnt3 + 1;
//分频为1分钟
always @(posedge clk or negedge rst_n)
	if(!rst_n)
		clk_1h <= 0;
	else if(cnt3 == 38'd179999999999)
		clk_1h <= ~clk_1h;
	else 
		clk_1h <= clk_1h;
endmodule 
module digital_clock_count_h(
	input clk,
	input rst_n,
	output reg [4:0]cnt_h  //计数24小时
    );
always @(negedge clk or negedge rst_n)
	if(!rst_n)
		cnt_h <= 0;
	else if(cnt_h == 5'd23)
		cnt_h <= 0;
	else 	
		cnt_h <= cnt_h + 1;
		
endmodule 
module digital_clock_time(
	input clk,
	input rst_n,
	input [5:0]cnt_s,
	input [5:0]cnt_f,
	input [4:0]cnt_h,
	output reg [3:0]bit_s,//个位秒
	output reg [3:0]tenbit_s,//十位秒
	output reg [3:0]bit_f,//个位分
	output reg [3:0]tenbit_f,//十位分
	output reg [3:0]bit_h,//个位时
	output reg [3:0]tenbit_h //十位时
    );
	
always @(posedge clk or negedge rst_n )
	if(!rst_n)
		begin 
			bit_s <= 0;
			tenbit_s <= 0;
		end
	else if (cnt_s < 6'd10)
		begin 
			bit_s <= (cnt_s%10);
			tenbit_s <= 0;
		end
	else if (cnt_s < 6'd20)
		begin 
			bit_s <= (cnt_s - 10);
			tenbit_s <= 1;
		end
	else if (cnt_s < 6'd30)
		begin 
			bit_s <= (cnt_s - 20);
			tenbit_s <= 2;
		end
	else if (cnt_s < 6'd40)
		begin 
			bit_s <= (cnt_s - 30);
			tenbit_s <= 3;
		end
	else if (cnt_s < 6'd50)
		begin 
			bit_s <= (cnt_s - 40);
			tenbit_s <= 4;
		end
	else if (cnt_s <= 6'd59)
		begin 
			bit_s <= (cnt_s - 50);
			tenbit_s <= 5;
		end
always @(posedge clk or negedge rst_n )
	if(!rst_n)
		begin 
			bit_f <= 0;
			tenbit_f <= 0;
		end
	else if (cnt_f < 6'd10)
		begin 
			bit_f <= (cnt_f%10);
			tenbit_f <= 0;
		end
	else if (cnt_f < 6'd20)
		begin 
			bit_f <= (cnt_f - 10);
			tenbit_f <= 1;
		end
	else if (cnt_f < 6'd30)
		begin 
			bit_f <= (cnt_f - 20);
			tenbit_f <= 2;
		end
	else if (cnt_f < 6'd40)
		begin 
			bit_f <= (cnt_f - 30);
			tenbit_f <= 3;
		end
	else if (cnt_f < 6'd50)
		begin 
			bit_f <= (cnt_f - 40);
			tenbit_f <= 4;
		end
	else if (cnt_f <= 6'd59)
		begin 
			bit_f <= (cnt_f - 50);
			tenbit_f <= 5;
		end
always @(posedge clk or negedge rst_n )
	if(!rst_n)
		begin 
			bit_h <= 0;
			tenbit_h <= 0;
		end
	else if (cnt_h < 5'd10)
		begin 
			bit_h <= (cnt_h%10);
			tenbit_h <= 0;
		end
	else if (cnt_h < 5'd20)
		begin 
			bit_h <= (cnt_h - 10);
			tenbit_h <= 1;
		end
	else if (cnt_h < 5'd23)
		begin 
			bit_h <= (cnt_h - 20);
			tenbit_h <= 2;
		end
endmodule 
module digital_clock_digital( input clk, input rst_n, input [3:0]bit_s,//个位秒 input [3:0]tenbit_s,//十位秒 input [3:0]bit_f,//个位分 input [3:0]tenbit_f,//十位分 input [3:0]bit_h,//个位时 input [3:0]tenbit_h, //十位时 output reg [7:0]sel,//片选信号 output reg [7:0]seg //段选信号 ); //1ms计数器 reg [16:0]cnt4; always @(posedge clk or negedge rst_n) if(!rst_n) cnt4 <= 0; else if(cnt4 == 99999)//1000000/10=100000 cnt4 <= 0; else cnt4 <= cnt4 + 1; //1ms使能时钟控制信号 reg clk_1ms; always @(posedge clk or negedge rst_n) if(!rst_n) clk_1ms <= 0; else if(cnt4 == 99999) clk_1ms <= 1; else clk_1ms <= 0; //位选计数器 reg [2:0]num_cnt; always @(posedge clk or negedge rst_n) if(!rst_n) num_cnt <= 0; else if(clk_1ms) num_cnt <= num_cnt + 1; //板上位选信号 共阳极 低电平有效 always @(posedge clk) case(num_cnt) 0:sel <=8'b1111_1110;//个位 1:sel <=8'b1111_1101;//十位 2:sel <=8'b1111_1011; 3:sel <=8'b1111_0111; 4:sel <=8'b1110_1111; 5:sel <=8'b1101_1111; 6:sel <=8'b1111_1111; 7:sel <=8'b1111_1111; endcase //数据分配 wire [31:0]data; assign data[3:0] = bit_s; assign data[7:4] = tenbit_s; assign data[11:8] = bit_f; assign data[15:12] = tenbit_f; assign data[19:16] = bit_h; assign data[23:20] = tenbit_h; /*assign data[27:24] = 0; assign data[31:28] = 0; */ reg [3:0]disp_tmp; always @(posedge clk) case(num_cnt) 0:disp_tmp <= data[3:0]; 1:disp_tmp <= data[7:4]; 2:disp_tmp <= data[11:8]; 3:disp_tmp <= data[15:12]; 4:disp_tmp <= data[19:16]; 5:disp_tmp <= data[23:20]; 6:disp_tmp <= data[27:24]; 7:disp_tmp <= data[31:28]; endcase //板上段选信号 共阳极 低电平有效 always @(posedge clk) case(disp_tmp) 4'd0:seg <= 8'b1100_0000; 4'd1:seg <= 8'b1111_1001; 4'd2:seg <= 8'b1010_0100; 4'd3:seg <= 8'b1011_0000; 4'd4:seg <= 8'b1001_1001; 4'd5:seg <= 8'b1001_0010; 4'd6:seg <= 8'b1000_0010; 4'd7:seg <= 8'b1111_1000; 4'd8:seg <= 8'b1000_0000; 4'd9:seg <= 8'b1001_0000; endcase endmodule
set_property IOSTANDARD LVCMOS33 [get_ports {seg[7]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[6]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[5]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[4]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[3]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[2]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[1]}]
set_property IOSTANDARD LVCMOS33 [get_ports {seg[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[7]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[6]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[5]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[4]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[3]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[2]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[1]}]
set_property IOSTANDARD LVCMOS33 [get_ports {sel[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports clk]
set_property IOSTANDARD LVCMOS33 [get_ports rst_n]
set_property PACKAGE_PIN E3 [get_ports clk]
set_property PACKAGE_PIN C12 [get_ports rst_n]
set_property PACKAGE_PIN U13 [get_ports {sel[7]}]
set_property PACKAGE_PIN K2 [get_ports {sel[6]}]
set_property PACKAGE_PIN T14 [get_ports {sel[5]}]
set_property PACKAGE_PIN P14 [get_ports {sel[4]}]
set_property PACKAGE_PIN J14 [get_ports {sel[3]}]
set_property PACKAGE_PIN T9 [get_ports {sel[2]}]
set_property PACKAGE_PIN J18 [get_ports {sel[1]}]
set_property PACKAGE_PIN J17 [get_ports {sel[0]}]
set_property PACKAGE_PIN R10 [get_ports {seg[1]}]
set_property PACKAGE_PIN K16 [get_ports {seg[2]}]
set_property PACKAGE_PIN K13 [get_ports {seg[3]}]
set_property PACKAGE_PIN P15 [get_ports {seg[4]}]
set_property PACKAGE_PIN T11 [get_ports {seg[5]}]
set_property PACKAGE_PIN L18 [get_ports {seg[6]}]
set_property PACKAGE_PIN H15 [get_ports {seg[7]}]
set_property PACKAGE_PIN T10 [get_ports {seg[0]}] 



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