目录
概述
该设计是用于体育比赛的数字秒表,基于FPGA在Quartus II 9.0sp2软件下应用VHDL语言编写程序,采用ALTRA公司CycloneII系列的EP2C8Q208芯片进行了计算机仿真，并给出了相应的仿真结果。本设计有效的克服了传统的数字秒表的缺点采用EDA技术采取自上而下的设计思路。绘制出了具体的逻辑电路，最后又通过硬件上对其进行调试和验证。该电路能够实现很好的计时功能,计时精度高，最长计时时间可达一个小时。
设计功能
1、完成一个带有时分秒显示的数字秒表；
2、12、24小时可以调节；
3、能作秒表计时；
4、能够倒计时显示;
数字秒表设计的目的
本次设计的目的就是在掌握EDA实验开发系统的初步使用基础上，了解EDA技术，对计算机系统中时钟控制系统进一步了解，掌握状态机工作原理，同时了解计算机时钟脉冲是怎么产生和工作的。（此处省略）
模块仿真
设计代码
（代码较长，完整工程免费分享，需要获取可关注：FPGA苑）
module time_clock(
clk,
reset_n,
hour_select_key,
second_counter_key,
second_countdown_key,
pause_key,
duan,
wei
);
input clk; //clk:50MHZ时钟输入；
input reset_n; //复位信号输入，低电平有效；
input hour_select_key; //12、24小时可以调节按键，当为'1'时为24，'0'时为12小时；
input second_counter_key; //当该按键为'1'时为秒表计时功能，'0'时为正常功能；
input second_countdown_key; //当该按键为'1'时为倒计时功能，'0'时为正常功能；
input pause_key; //暂停功能按键，进行秒表计时和倒计时时可以通过该按键进行暂停，'1'暂停，'0'继续
output [7:0] duan; //duan:数码管段码；
output [7:0] wei; //wei:数码管位码；
reg [7:0] duan; //duan:数码管段码；
reg [7:0] wei; //wei:数码管位码；
reg [24:0] count; //1HZ时钟计数器
reg [13:0] count2; //扫描时钟计数器
reg clk_1hz; //1HZ时钟信号
reg [3:0] miao_ge; //秒个位数BCD码
reg [2:0] miao_shi; //秒十位BCD二进制码
reg [3:0] fen_ge; //分钟个位数
reg [2:0] fen_shi; //分钟十位数
reg [1:0] shi_ge; //时钟个位数
reg [1:0] shi_shi; //时钟十位数
reg [1:0] shi_select_ge; //时钟选择个位数，用于调节时制
reg [1:0] shi_select_shi; //时钟选择十位数，用于调节时制
reg clk_scan; //数码管扫描时钟
reg [2:0] select; //用于扫描时选择显示位码
//****************************************************************************************************
// 模块名称:秒时钟分频模块
// 功能描述:
//****************************************************************************************************
always @(posedge clk or negedge reset_n)//1HZ时钟进程
begin
if(reset_n == 1'b0)
begin
count <= 25'd0;
clk_1hz <= 1'b0;
end
else
if(count == 25'd25000000)
begin
clk_1hz <= ~clk_1hz;
count <= 25'd0;
end
else
count <= count + 1'b1;
end
reg [17:0] counter_count;
reg clk_100hz;
always @(posedge clk or negedge reset_n)//100HZ时钟进程
begin
if(reset_n == 1'b0)
begin
counter_count <= 18'd0;
clk_100hz <= 1'b0;
end
else
if(~pause_key == 1'b0)
if(counter_count == 18'd250000)
begin
clk_100hz <= ~clk_100hz;
counter_count <= 18'd0;
end
else
counter_count <= counter_count + 1'b1;
else
begin
clk_100hz <= 1'b0;
counter_count <= 18'd0;
end
end
//****************************************************************************************************
// 模块名称:计时调节模块
// 功能描述:
//****************************************************************************************************
always @(posedge clk or negedge reset_n)//1HZ时钟进程
begin
if(reset_n == 1'b0)
begin
shi_select_ge <= 2'd3;
shi_select_shi <= 2'd2;
end
else
if(hour_select_key == 1'b1)//12、24小时可以调节按键，当为'1'时为24，'0'时为12小时
begin
shi_select_ge <= 2'd3;
shi_select_shi <= 2'd2;
end
else
begin
shi_select_ge <= 2'd1;
shi_select_shi <= 2'd1;
end
end
//****************************************************************************************************
// 模块名称:秒计时模块
// 功能描述:
//****************************************************************************************************
always @(posedge clk_1hz or negedge reset_n)//秒分时各位累加功能进程
begin
if(reset_n == 1'b0)
begin
miao_ge <= 4'd9;
miao_shi <= 3'd5;
fen_ge <= 4'd9;
fen_shi <= 3'd5;
shi_ge <= 2'd3;
shi_shi <= 2'd2;
end
else
if(miao_ge ==4'd9)
begin
miao_ge <= 4'd0;
if(miao_shi == 3'd5)
begin
miao_shi <= 3'd0;
if(fen_ge == 4'd9)
begin
fen_ge <= 4'd0;
if(fen_shi == 3'd5)
begin
fen_shi <= 3'd0;
if(shi_ge == shi_select_ge)//24小时制对应3，12小时制则对应1
begin
shi_ge <= 2'd0;
if(shi_shi == shi_select_shi)//24小时制对应2，12小时制则对应1
shi_shi <= 2'd0;
else
shi_shi <= shi_shi + 1'b1;
end
else
shi_ge <= shi_ge + 1'b1;
end
else
fen_shi <= fen_shi + 1'b1;
end
else
fen_ge <= fen_ge + 1'b1;
end
else
miao_shi <= miao_shi + 1'b1;
end
else
miao_ge <= miao_ge + 1'b1;
end
//****************************************************************************************************
// 模块名称:数码管位选择时钟产生模块
// 功能描述:
//****************************************************************************************************
always @(posedge clk or negedge reset_n)//数码管扫描时钟产生进程
begin
if(reset_n == 1'b0)
begin
count2 <= 14'd0;
clk_scan <= 1'b0;
end
else
if(count2 == 14'd10000)
begin
count2 <= 14'd0;
clk_scan <= ~clk_scan;
end
else
count2 <= count2 + 1'b1;
end
//****************************************************************************************************
// 模块名称:数码管位选择产生信号模块
// 功能描述:
//****************************************************************************************************
always @(posedge clk_scan or negedge reset_n)
begin
if(reset_n == 1'b0)
select <= 3'b000;
else
select <= select + 1'b1;
end
//****************************************************************************************************
// 模块名称:秒表计时
// 功能描述:秒表计时
//****************************************************************************************************
reg [3:0] counter_haomiao_ge; //秒表计时,毫秒个位数BCD码
reg [3:0] counter_haomiao_shi; //秒表计时,毫秒十位数BCD码
reg [3:0] counter_miao_ge; //秒表计时,秒个位数BCD码
reg [2:0] counter_miao_shi; //秒表计时,秒十位BCD二进制码
reg [3:0] counter_fen_ge; //秒表计时,分钟个位数
reg [2:0] counter_fen_shi; //秒表计时,分钟十位数
reg [1:0] counter_shi_ge; //秒表计时,时钟个位数
reg [1:0] counter_shi_shi; //秒表计时,时钟十位数
always @(posedge clk_100hz or negedge reset_n)
begin
if(reset_n == 1'b0)
begin
counter_haomiao_ge <= 4'd0;
counter_haomiao_shi <= 4'd0;
counter_miao_ge <= 4'd0;
counter_miao_shi <= 3'd0;
counter_fen_ge <= 4'd0;
counter_fen_shi <= 3'd0;
counter_shi_ge <= 2'd0;
counter_shi_shi <= 2'd0;
end
else
if(~second_counter_key == 1'b1)
if(counter_haomiao_ge == 4'd9)
begin
counter_haomiao_ge <= 4'd0;
if(counter_haomiao_shi == 4'd9)
begin
counter_haomiao_shi <= 4'd0;
if(counter_miao_ge ==4'd9)
begin
counter_miao_ge <= 4'd0;
if(counter_miao_shi == 3'd5)
begin
counter_miao_shi <= 3'd0;
if(counter_fen_ge == 4'd9)
begin
counter_fen_ge <= 4'd0;
if(counter_fen_shi == 3'd5)
begin
counter_fen_shi <= 3'd0;
if(counter_shi_ge == 2'd3)//24小时制对应3，12小时制则对应1
begin
counter_shi_ge <= 2'd0;
if(counter_shi_shi == 2'd2)//24小时制对应2，12小时制则对应1
counter_shi_shi <= 2'd0;
else
counter_shi_shi <= counter_shi_shi + 1'b1;
end
else
counter_shi_ge <= counter_shi_ge + 1'b1;
end
else
counter_fen_shi <= counter_fen_shi + 1'b1;
end
else
counter_fen_ge <= counter_fen_ge + 1'b1;
end
else
counter_miao_shi <= counter_miao_shi + 1'b1;
end
else
counter_miao_ge <= counter_miao_ge + 1'b1;
end
else
counter_haomiao_shi <= counter_haomiao_shi + 1'b1;
end
else
counter_haomiao_ge <= counter_haomiao_ge + 1'b1;
else
begin
counter_haomiao_ge <= 4'd0;
counter_haomiao_shi <= 4'd0;
counter_miao_ge <= 4'd0;
counter_miao_shi <= 3'd0;
counter_fen_ge <= 4'd0;
counter_fen_shi <= 3'd0;
counter_shi_ge <= 2'd0;
counter_shi_shi <= 2'd0;
end
end
//****************************************************************************************************
// 模块名称:倒计时模块
// 功能描述:
//****************************************************************************************************
reg [3:0] countdown_haomiao_ge; //倒计时，毫秒个位数BCD码
reg [3:0] countdown_haomiao_shi; //倒计时，毫秒十位数BCD码
reg [3:0] countdown_miao_ge; //倒计时，秒个位数BCD码
reg [2:0] countdown_miao_shi; //倒计时，秒十位BCD二进制码
always @(posedge clk_100hz or negedge reset_n)//秒分时各位累加功能进程
begin
if(reset_n == 1'b0)
begin
countdown_haomiao_ge <= 4'd9;
countdown_haomiao_shi <= 4'd9;
countdown_miao_ge <= 4'd9;
countdown_miao_shi <= 3'd5;
end
else
if(~second_countdown_key == 1'b1)
if(countdown_haomiao_ge == 4'd0)
begin
countdown_haomiao_ge <= 4'd9;
if(countdown_haomiao_shi == 4'd0)
begin
countdown_haomiao_shi <= 4'd9;
if(countdown_miao_ge ==4'd0)
begin
countdown_miao_ge <= 4'd9;
if(countdown_miao_shi == 3'd0)
begin
countdown_miao_shi <= 3'd5;
end
else
countdown_miao_shi <= countdown_miao_shi - 1'b1;
end
else
countdown_miao_ge <= countdown_miao_ge - 1'b1;
end
else
countdown_haomiao_shi <= countdown_haomiao_shi - 1'b1;
end
else
countdown_haomiao_ge <= countdown_haomiao_ge - 1'b1;
else
begin
countdown_haomiao_ge <= 4'd9;
countdown_haomiao_shi <= 4'd9;
countdown_miao_ge <= 4'd9;
countdown_miao_shi <= 3'd5;
end
end
//****************************************************************************************************
// 模块名称:功能选择模块
// 功能描述:
//****************************************************************************************************
reg [3:0] reg_haomiao_ge; //毫秒个位数BCD码
reg [3:0] reg_haomiao_shi; //毫秒十位数BCD码
reg [3:0] reg_miao_ge; //秒个位数BCD码
reg [2:0] reg_miao_shi; //秒十位BCD二进制码
reg [3:0] reg_fen_ge; //分钟个位数
reg [2:0] reg_fen_shi; //分钟十位数
reg [3:0] reg_shi_ge; //时钟个位数
reg [1:0] reg_shi_shi; //时钟十位数
always @(posedge clk or negedge reset_n)
begin
if(reset_n == 1'b0)
begin
reg_haomiao_ge <= 4'd9;
reg_haomiao_shi <= 4'd9;
reg_miao_ge <= 4'd9;
reg_miao_shi <= 3'd5;
reg_fen_ge <= 4'd9;
reg_fen_shi <= 3'd5;
reg_shi_ge <= 4'd3;
reg_shi_shi <= 2'd2;
end
else
begin
case({~second_counter_key,~second_countdown_key})
2'b10://秒表功能
begin
reg_haomiao_ge <= counter_haomiao_ge;
reg_haomiao_shi <= counter_haomiao_shi;
reg_miao_ge <= counter_miao_ge;
reg_miao_shi <= counter_miao_shi;
reg_fen_ge <= counter_fen_ge;
reg_fen_shi <= counter_fen_shi;
reg_shi_ge <= counter_shi_ge;
reg_shi_shi <= counter_shi_shi;
end
2'b01://倒计时功能
begin
reg_haomiao_ge <= countdown_haomiao_ge;
reg_haomiao_shi <= countdown_haomiao_shi;
reg_miao_ge <= countdown_miao_ge;
reg_miao_shi <= countdown_miao_shi;
reg_fen_ge <= 4'hf; //不进行显示
reg_fen_shi <= 3'b111; //不进行显示
reg_shi_ge <= 4'b1111; //不进行显示
reg_shi_shi <= 2'b11; //不进行显示
end
default://正常功能，显示时分秒
begin
reg_haomiao_ge <= 4'hf; //不进行显示
reg_haomiao_shi <= 4'hf; //不进行显示
reg_miao_ge <= miao_ge;
reg_miao_shi <= miao_shi;
reg_fen_ge <= fen_ge;
reg_fen_shi <= fen_shi;
reg_shi_ge <= shi_ge;
reg_shi_shi <= shi_shi;
end
endcase
end
end
//****************************************************************************************************
// 模块名称:译码电路
// 功能描述:
//****************************************************************************************************
always @(posedge clk)//敏感信号列表reg_haomiao_ge or miao_ge or miao_shi or fen_ge or fen_shi or shi_ge or shi_shi or select
begin
if(select == 3'd0)
begin
wei <= 8'b11111110;//毫秒个位数显示
case(reg_haomiao_ge)
4'b0000:duan <= 8'b1100_0000;//0
4'b0001:duan <= 8'b1111_1001;//1
4'b0010:duan <= 8'b1010_0100;//2
4'b0011:duan <= 8'b1011_0000;//3
4'b0100:duan <= 8'b1001_1001;//4
4'b0101:duan <= 8'b1001_0010;//5
4'b0110:duan <= 8'b1000_0010;//6
4'b0111:duan <= 8'b1111_1000;//7
4'b1000:duan <= 8'b1000_0000;//8
4'b1001:duan <= 8'b1001_0000;//9
default:duan <= 8'hff;
endcase
end
else if(select == 3'd1)
begin
wei <= 8'b11111101;//毫秒十位数显示
case(reg_haomiao_shi)
4'b0000:duan <= 8'b1100_0000;//0
4'b0001:duan <= 8'b1111_1001;//1
4'b0010:duan <= 8'b1010_0100;//2
4'b0011:duan <= 8'b1011_0000;//3
4'b0100:duan <= 8'b1001_1001;//4
4'b0101:duan <= 8'b1001_0010;//5
4'b0110:duan <= 8'b1000_0010;//6
4'b0111:duan <= 8'b1111_1000;//7
4'b1000:duan <= 8'b1000_0000;//8
4'b1001:duan <= 8'b1001_0000;//9
default:duan <= 8'hff;
endcase
end
else if(select == 3'd2)
begin
wei <= 8'b11111011;//秒个位数显示
case(reg_miao_ge)
4'b0000:duan <= 8'b1100_0000;//0
4'b0001:duan <= 8'b1111_1001;//1
4'b0010:duan <= 8'b1010_0100;//2
4'b0011:duan <= 8'b1011_0000;//3
4'b0100:duan <= 8'b1001_1001;//4
4'b0101:duan <= 8'b1001_0010;//5
4'b0110:duan <= 8'b1000_0010;//6
4'b0111:duan <= 8'b1111_1000;//7
4'b1000:duan <= 8'b1000_0000;//8
4'b1001:duan <= 8'b1001_0000;//9
default:duan <= 8'hff;
endcase
end
else if(select == 3'd3)
begin
wei <= 8'b11110111;//秒十位数显示
case(reg_miao_shi)
3'b000:duan <= 8'b1100_0000;
3'b001:duan <= 8'b1111_1001;
3'b010:duan <= 8'b1010_0100;
3'b011:duan <= 8'b1011_0000;
3'b100:duan <= 8'b1001_1001;
3'b101:duan <= 8'b1001_0010;
3'b110:duan <= 8'b1000_0010;
default:duan <= 8'hff;
endcase
end
else if(select == 3'd4)
begin
wei <= 8'b11101111;//分钟个位数显示
case(reg_fen_ge)
4'b0000:duan <= 8'b1100_0000;
4'b0001:duan <= 8'b1111_1001;
4'b0010:duan <= 8'b1010_0100;
4'b0011:duan <= 8'b1011_0000;
4'b0100:duan <= 8'b1001_1001;
4'b0101:duan <= 8'b1001_0010;
4'b0110:duan <= 8'b1000_0010;
4'b0111:duan <= 8'b1111_1000;
4'b1000:duan <= 8'b1000_0000;
4'b1001:duan <= 8'b1001_0000;
default:duan <= 8'hff;
endcase
end
else if(select == 3'd5)
begin
wei <= 8'b11011111;//分钟十位数显示
case(reg_fen_shi)
3'b000:duan <= 8'b1100_0000;
3'b001:duan <= 8'b1111_1001;
3'b010:duan <= 8'b1010_0100;
3'b011:duan <= 8'b1011_0000;
3'b100:duan <= 8'b1001_1001;
3'b101:duan <= 8'b1001_0010;
3'b110:duan <= 8'b1000_0010;
default:duan <= 8'hff;
endcase
end
else if(select == 3'd6)
begin
wei <= 8'b10111111;//时钟个位数显示
case(reg_shi_ge)
4'b0000:duan <= 8'b1100_0000;
4'b0001:duan <= 8'b1111_1001;
4'b0010:duan <= 8'b1010_0100;
4'b0011:duan <= 8'b1011_0000;
default:duan <= 8'hff;
endcase
end
else
begin
wei <= 8'b01111111;//时钟十位数显示
case(reg_shi_shi)
3'b000:duan <= 8'b1100_0000;
3'b001:duan <= 8'b1111_1001;
3'b010:duan <= 8'b1010_0100;
default:duan <= 8'hff;
endcase
end
end
endmodule