lab14 简单玩一把封装--独立按键的封装
本实验利用前面的按键消抖模块和DE2上的资源，设计一个利用pwm控制led发光亮度的实验。
1 简介
时钟：50MHz，CLOCK_50;
复位：SW1，拨下为复位；
5个输入：SW0，KEY[3:0]；
输出：LEDG8；
5个输入代表5种不同的PWM，即不同占空比的1KHz的脉冲信号，那么LED的亮的时间也不同，人眼看到的亮度就不同。
2 设计
工程结构
源码
1）key_interface_demo.v,本例的顶层模块。调用按键模块和可调pwm模块。
1 module key_interface_demo
2 (
3 input clk,
4 input rst_n,
5 input [4:0] key_in,
6 output led
7 );
8
9 wire [4:0] key_out;
10
11 key_interface U1
12 (
13 .clk(clk),
14 .rst_n(rst_n),
15 .key_in(key_in),
16 .key_out(key_out)
17 );
18
19 optional_pwm_module U2
20 (
21 .clk(clk),
22 .rst_n(rst_n),
23 .option_key(key_out),
24 .led(led)
25 );
26
27 endmodule
28
2) key_interface.v，按键模块，5个按键例化5次。
1 module key_interface
2 (
3 input clk,
4 input rst_n,
5 input [4:0] key_in,
6 output [4:0] key_out
7 );
8
9 debounce_module2 U1
10 (
11 .clk(clk),
12 .rst_n(rst_n),
13 .pin_in(key_in[4]),
14 .pin_out(key_out[4])
15 );
16
17 debounce_module2 U2
18 (
19 .clk(clk),
20 .rst_n(rst_n),
21 .pin_in(key_in[3]),
22 .pin_out(key_out[3])
23 );
24
25 debounce_module2 U3
26 (
27 .clk(clk),
28 .rst_n(rst_n),
29 .pin_in(key_in[2]),
30 .pin_out(key_out[2])
31 );
32
33 debounce_module2 U4
34 (
35 .clk(clk),
36 .rst_n(rst_n),
37 .pin_in(key_in[1]),
38 .pin_out(key_out[1])
39 );
40
41 debounce_module2 U5
42 (
43 .clk(clk),
44 .rst_n(rst_n),
45 .pin_in(key_in[0]),
46 .pin_out(key_out[0])
47 );
48
49 endmodule
50
3) debounce_module2.v，按键消抖模块。
1 module debounce_module2
2 (
3 clk,rst_n,pin_in,pin_out
4 );
5
6 input clk;
7 input rst_n;
8 input pin_in;
9 output pin_out;
10
11 wire h2l;
12 wire l2h;
13
14 detect_module U1
15 (
16 .clk(clk),
17 .rst_n(rst_n),
18 .pin_in(pin_in),
19 .h2l(h2l),
20 .l2h(l2h)
21 );
22
23 delay_module U2
24 (
25 .clk(clk),
26 .rst_n(rst_n),
27 .h2l(h2l),
28 .l2h(l2h),
29 .pin_out(pin_out)
30 );
31
32 endmodule
4) detect_module.v，电平检测模块。
1 module detect_module
2 (
3 clk,rst_n,pin_in,h2l,l2h
4 );
5
6 input clk;
7 input rst_n;
8 input pin_in;
9 output h2l;
10 output l2h;
11
12 parameter T100US = 13'd5000;
13
14 reg [12:0] count1; //定时器
15 reg isen;
16
17 always @(posedge clk or negedge rst_n)
18 if (!rst_n)
19 begin
20 count1 <= 13'd0;
21 isen <= 1'b0;
22 end
23 else if (count1 == T100US)
24 isen <= 1'b1;
25 else
26 count1 <= count1 + 1'b1;
27
28 reg h2l_f1;
29 reg h2l_f2;
30 reg l2h_f1;
31 reg l2h_f2;
32
33 always @(posedge clk or negedge rst_n)
34 if (!rst_n)
35 begin
36 h2l_f1 <= 1'b1;
37 h2l_f2 <= 1'b1;
38 l2h_f1 <= 1'b0;
39 l2h_f2 <= 1'b0;
40 end
41 else
42 begin
43 h2l_f1 <= pin_in;
44 h2l_f2 <= h2l_f1;
45 l2h_f1 <= pin_in;
46 l2h_f2 <= l2h_f1;
47 end
48
49 assign h2l = isen ? (h2l_f2 & !h2l_f1) : 1'b0;
50 assign l2h = isen ? (!l2h_f2 & l2h_f1) : 1'b0;
51
52 endmodule
53
5) delay_module.v，10ms延时模块。
1 module delay_module
2 (
3 clk,rst_n,h2l,l2h,pin_out
4 );
5
6 input clk;
7 input rst_n;
8 input h2l;
9 input l2h;
10 output pin_out;
11
12 parameter T1MS = 16'd50_000;
13
14 reg [15:0] count1; //1ms定时器
15
16 always @(posedge clk or negedge rst_n)
17 if (!rst_n)
18 count1 <= 16'd0;
19 else if (iscount && count1 == T1MS)
20 count1 <= 16'd0;
21 else if (iscount)
22 count1 <= count1 + 1'b1;
23 else if (!iscount)
24 count1 <= 16'd0;
25
26 reg [3:0] count_ms; //10ms计数器
27
28 always @(posedge clk or negedge rst_n)
29 if (!rst_n)
30 count_ms <= 4'd0;
31 else if (iscount && count1 == T1MS)
32 count_ms <= count_ms + 1'b1;
33 else if (!iscount)
34 count_ms <= 4'd0;
35
36 reg iscount; //计数使能
37 reg rpin_out;
38 reg [1:0] i;
39
40 always @(posedge clk or negedge rst_n)
41 if (!rst_n)
42 begin
43 iscount <= 1'b0;
44 rpin_out <= 1'b0;
45 i <= 2'd0;
46 end
47 else
48 case(i)
49 2'd0:
50 if (h2l)
51 i <= 2'd1;
52 else if (l2h)
53 i <= 2'd3;
54 2'd1: //延迟10ms，输出高电平
55 if (count_ms == 4'd10)
56 begin
57 iscount <= 1'b0;
58 rpin_out <= 1'b1;
59 i <= 2'd2;
60 end
61 else
62 iscount <= 1'b1;
63 2'd2:
64 begin
65 rpin_out <= 1'b0;
66 i <= 2'd0;
67 end
68 2'd3: //延迟10ms
69 if (count_ms == 4'd10)
70 begin
71 iscount <= 1'b0;
72 i <= 2'd0;
73 end
74 else
75 iscount <= 1'b1;
76 endcase
77
78 assign pin_out = rpin_out;
79
80 endmodule
81
6) optional_pwm_module.v,可调pwm模块。
1 module optional_pwm_module
2 (
3 input clk,
4 input rst_n,
5 input [4:0] option_key,
6 output led
7 );
8
9 parameter SEGMENT = 8'd195; //3.9us
10
11 reg [7:0] c1; //3.9us定时器
12
13 always @(posedge clk or negedge rst_n)
14 if (!rst_n)
15 c1 <= 7'd0;
16 else if (c1 == SEGMENT)
17 c1 <= 7'd0;
18 else
19 c1 <= c1 + 1'b1;
20
21 reg [7:0] system_seg; //pwm块计数器
22
23 always @(posedge clk or negedge rst_n)
24 if (!rst_n)
25 system_seg <= 8'd0;
26 else if (system_seg == 8'd255)
27 system_seg <= 8'd0;
28 else if (c1 == SEGMENT)
29 system_seg <= system_seg + 1'b1;
30
31 reg [7:0] option_seg; //可调pwm块
32
33 always @(posedge clk or negedge rst_n)
34 if (!rst_n)
35 option_seg <= 8'd0;
36 else if (option_key[4]) //segment + 10
37 if (option_seg < 8'd245)
38 option_seg <= option_seg + 8'd10;
39 else
40 option_seg <= 8'd255;
41 else if (option_key[3]) //segment - 10
42 if (option_seg > 8'd10)
43 option_seg <= option_seg - 8'd10;
44 else
45 option_seg <= 8'd0;
46 else if (option_key[2]) //segment + 1
47 if (option_seg < 8'd255)
48 option_seg <= option_seg + 8'd1;
49 else
50 option_seg <= 8'd255;
51 else if (option_key[1]) //segment - 1
52 if (option_seg > 8'd0)
53 option_seg <= option_seg - 8'd1;
54 else
55 option_seg <= 8'd0;
56 else if (option_key[0]) //segment = half
57 option_seg <= 8'd127;
58
59 assign led = (system_seg < option_seg) ? 1'b1: 1'b0;
60
61 endmodule
62
63
RTL Viewer
引脚分配
1 #CLOCK_50
2 set_location_assignment pin_n2 -to clk
3 #SW1
4 set_location_assignment pin_n26 -to rst_n
5 #SW0
6 set_location_assignment pin_n25 -to key_in[4]
7 #KEY[3:0]
8 set_location_assignment pin_w26 -to key_in[3]
9 set_location_assignment pin_p23 -to key_in[2]
10 set_location_assignment pin_n23 -to key_in[1]
11 set_location_assignment pin_g26 -to key_in[0]
12 #LEDG8
13 set_location_assignment pin_y12 -to led
问题
warning：found pins functioning as undefined clocks and/or memory enables.
原因：为指定时钟。
解决方法：
assignment / setting / timing analysis setting / classic timing analyzer settings / default required fmax / individual clocks / new / applies to node / clk / clock setting /
... / ok.
或者set_instance_assignment -name CLOCK_50 -to clock
3 小结
由例化调用，小体验一把封装是怎么回事儿。