//顶层
module timer_top(
input clk_12M,//12Mhz时钟
input reset,//复位
input stop,//暂停
output [1:0]wela,//位选
output [7:0]dula1,//第一个数码管段选
output [7:0]dula2//第二个数码管段选
);
wire [7:0]sec;
time_cnt u1(
.clk_12M(clk_12M),
.reset(reset),
.stop(stop),
.sec(sec)
);//例化分频计数模块
display u2(
.clk_12M(clk_12M),
.sec(sec),
.wela(wela),
.dula1(dula1),
.dula2(dula2)
);//例化显示模块
endmodule
//分频计数
module time_cnt(
input clk_12M,
input reset,
input stop,
output [7:0] sec
);
/*12M时钟分频1s 计数6M次*/
reg [23:0]cnt;
reg clk_1s;
always @(posedge clk_12M or negedge stop)
begin
if(!stop)//暂停信号为0时有效
begin
cnt <= 0;
end//停止信号有效时，暂停
else if(cnt == 24'h5b8d80)//计数为5999999
begin
clk_1s <= ~clk_1s;
cnt <= 0;
end
else
begin
cnt <= cnt+1;
clk_1s <= clk_1s;
end//暂停信号无效时继续计时
end
/*用于产生1s的秒表计数*/
reg [7:0]sec_reg=0;
always @(posedge clk_1s or negedge reset)
begin
if(!reset)//复位信号为0时有效
begin
sec_reg <= 0;//复位信号有效时置0
end
else if(sec_reg[3:0] == 4'd9)//秒个位计数到9
begin
if(sec_reg[7:4] == 4'd5)//秒十位计数到5
begin
sec_reg <= 0;//清0
end
else
begin
sec_reg[7:4] <= sec_reg[7:4] + 1;//秒十位加1
sec_reg[3:0] <= 0;//秒个位清零
end
end
else
begin
sec_reg[3:0] <= sec_reg[3:0] + 1;
end
end
assign sec = sec_reg;
endmodule
//显示
module display(
input clk_12M,
input [7:0]sec,
output reg [1:0]wela=0,
output reg [7:0]dula1=0,
output reg [7:0]dula2=0
);
/*数码管需要动态扫描，所以产生一个1ms的时钟*/
reg [12:0]cnt;
reg clk_1ms;
always @(posedge clk_12M)
begin
if(cnt == 13'h1770)
begin
cnt <= 0;
clk_1ms <= ~clk_1ms;
end
else
begin
cnt <= cnt + 1;
clk_1ms <= clk_1ms;
end
end
reg state;
reg [3:0]sec_reg1;
reg [3:0]sec_reg2;
always @(posedge clk_1ms)
case(state)//位选
0:begin
wela<=2'b01;state<=1;sec_reg2 <= sec[3:0];
end
1:begin
wela<=2'b10;state<=0;sec_reg1 <= sec[7:4];
end
endcase
always @(posedge clk_12M)
begin
case(sec_reg1)
0:dula1 <= 8'h3f;
1:dula1 <= 8'h06;
2:dula1 <= 8'h5b;
3:dula1 <= 8'h4f;
4:dula1 <= 8'h66;
5:dula1 <= 8'h6d;
6:dula1 <= 8'h7d;
7:dula1 <= 8'h07;
8:dula1 <= 8'h7f;
9:dula1 <= 8'h6f;
endcase
end//第一个数码管段选0~9
always @(posedge clk_12M)
begin
case(sec_reg2)
0:dula2 <= 8'h3f;
1:dula2 <= 8'h06;
2:dula2 <= 8'h5b;
3:dula2 <= 8'h4f;
4:dula2 <= 8'h66;
5:dula2 <= 8'h6d;
6:dula2 <= 8'h7d;
7:dula2 <= 8'h07;
8:dula2 <= 8'h7f;
9:dula2 <= 8'h6f;
endcase
end//第二个数码管段选0~9
endmodule
//测试文件
module timer_tb();
reg clk_12M;
reg stop;
reg reset;
wire [7:0]dula1;
wire [7:0]dula2;
wire [1:0]wela;
timer_top u1(
.clk_12M(clk_12M),
.stop(stop),
.reset(reset),
.dula1(dula1),
.dula2(dula2),
.wela(wela)
);
initial
begin
clk_12M=1;
reset=0;
stop=0;
#10 reset=1;stop=1;
#20 stop=0;
#5 reset=0;
#20 $stop;
end
always #1 clk_12M=~clk_12M;
endmodule
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