Note
此笔记针对西南交通大学2023-2024学年上半学期开设的计组实验课
1 实验内容
矩阵键盘值扫描读取及显示电路的设计
2 代码/原理图
2.1 顶层文件
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module EXP2(
clk,
KEY_R,
KEY_C,
out,
ins_num,
codeout,
sel
);
input clk;
input [3:0] KEY_R;
output reg[3:0] KEY_C = 4'b0111;
output reg[31:0] out= 32'h0000_0000;
output [3:0] ins_num;
output [6:0] codeout;
output wire[2:0] sel;
reg [31:0]timer = 32'b1;
reg [1:0] state_machine = 2'b0;
reg valid_input=1;
//根据按钮的列扫描信号和行输入信号判断按钮是否被按下
always @(posedge clk)
begin
state_machine = state_machine + 1'b1;
case (state_machine)
2'b00: KEY_C <= 4'b1110;
2'b01: KEY_C <= 4'b1101;
2'b10: KEY_C <= 4'b1011;
2'b11: KEY_C <= 4'b0111;
endcase
valid_input=!(KEY_R == 4'b1111);
begin
if(!valid_input)
begin
if(timer == 32'b0)
begin
timer = 32'd100001;
end
timer = timer + 1'b1;
end
else if(timer > 32'd100000)
begin
timer = 32'b1;
//置数没有在冷却阶段
out=out<<4;
out[3:0] = ins_num[3:0];
end
end
end
key2num k2n(clk,KEY_R,KEY_C,ins_num);
segment_displays sg(clk,out,codeout,sel);
endmodule
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2.2 根据键盘按键获得输入的值
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module key2num(clk,KEY_R,KEY_C,ins_num);
input clk;
input [3:0] KEY_R,KEY_C;
output reg [3:0] ins_num=0;
always@(*)
case ({KEY_C, KEY_R})
8'b1011_1110: ins_num = 4'd0;
8'b0111_0111: ins_num = 4'd1;
8'b1011_0111: ins_num = 4'd2;
8'b1101_0111: ins_num = 4'd3;
8'b0111_1011: ins_num = 4'd4;
8'b1011_1011: ins_num = 4'd5;
8'b1101_1011: ins_num = 4'd6;
8'b0111_1101: ins_num = 4'd7;
8'b1011_1101: ins_num = 4'd8;
8'b1101_1101: ins_num = 4'd9;
8'b1110_0111: ins_num = 4'd10;
8'b1110_1011: ins_num = 4'd11;
8'b1110_1101: ins_num = 4'd12;
8'b1110_1110: ins_num = 4'd13;
8'b0111_1110: ins_num = 4'd14;
8'b1101_1110: ins_num = 4'd15;
endcase
endmodule
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2.3 7段数码管译码器
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module segment_displays(clk,N,seg,sel);
input clk;
input [31:0] N;
output reg [7:0] seg;
output reg [2:0] sel;
reg [3:0]num;
always@(posedge clk)
begin
sel<=sel+1;
case(sel)
3'b110:num<=N[3:0];
3'b101:num<=N[7:4];
3'b100:num<=N[11:8];
3'b011:num<=N[15:12];
3'b010:num<=N[19:16];
3'b001:num<=N[23:20];
3'b000:num<=N[27:24];
3'b111:num<=N[31:28];
endcase
end
always@(num)
begin
case(num)
4'b0000:seg<=8'b00111111; //"0"
4'b0001:seg<=8'b00000110; //"1"
4'b0010:seg<=8'b01011011; //"2"
4'b0011:seg<=8'b01001111; //"3”
4'b0100:seg<=8'b01100110; //"4"
4'b0101:seg<=8'b01101101; //"5"
4'b0110:seg<=8'b01111101; //"6"
4'b0111:seg<=8'b00000111; //"8"
4'b1000:seg<=8'b01111111; //"8"
4'b1001:seg<=8'b01101111; //"9"
4'b1010:seg<=8'b01110111; //"A"
4'b1011:seg<=8'b01111100; //"b"
4'b1100:seg<=8'b00111001; //"c"
4'b1101:seg<=8'b01011110; //"d"
4'b1110:seg<=8'b01111001; //"E"
4'b1111:seg<=8'b01110001; //"F"
default:seg<=8'b00000000; //"dark"
endcase
end
endmodule
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2.4 仿真用testbench
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`timescale 1ns/1ns
module exp2_tb;
reg clk;
reg [3:0] key_r=4'b0111;
wire [3:0] key_c,out,ins_num;
wire [7:0] codeout;
initial
begin
clk=1'b0;
end
always #50 clk=~clk;
always@(posedge clk)
begin
case(key_r)
4'b0111:key_r=4'b1011;
4'b1011:key_r=4'b1101;
4'b1101:key_r=4'b1110;
4'b1110:key_r=4'b0111;
endcase
end
EXP2 U(
.clk(clk),
.KEY_R(key_r),
.KEY_C(key_c),
.out(out),
.ins_num(ins_num),
.codeout(codeout)
);
endmodule
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3 引脚分配
4 仿真波形
Note
由于设计的防抖模块会造成out和codeout信号延迟输出，此处仅关注ins_num的值
5 源码已上传github
github仓库：
swjtu_computer_organization_exp2_matrixkeyboard
