矩阵键盘的试验,采用三段式状态机处理方法。
难点在于检测状态机中：按键消抖以后逐列检测。
电路图：
代码：
/********************************Copyright**************************************
**----------------------------File information--------------------------
** File name :keyboard.v
** CreateDate :2015.04
** Funtions :4x4矩阵键盘
** Operate on :M5C06N3L114C7
** Copyright :All rights reserved.
** Version :V1.0
**---------------------------Modify the file information----------------
** Modified by :
** Modified data :
** Modify Content:
*******************************************************************************/
module keyboard(
clk,
rst_n,
l_in,
h_out,
test_1,
test_2,
key_val,
key_val_flag
);
input clk; /* clk = 24M */
input rst_n;
input [3:0] l_in; //列输入，一般接上拉，为高电平
output test_1;
output test_2;
output [3:0] h_out; //行输出信号，低有效
output [3:0] key_val; //按键值，输出
output key_val_flag;
wire [3:0] key_val;
reg test_1;
reg test_2;
//*************************************
/* 分频?*20ms，用于消抖 .状态机直接用clk_20ms，则可以跳过消抖*/
// localparam t_20ms = 17‘d239999;
localparam t_20ms = 17‘d23;
reg [17:0] cnt;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
begin
cnt <= ‘d0;
end
else
begin
if(cnt == t_20ms) cnt <= ‘d0;
else cnt <= cnt + ‘d1;
end
end
wire shake_over = (cnt == t_20ms);
//******************状态机******************
localparam NO_KEY_pressed = 3‘d0; /* 初始化 */
localparam key_shake_1 = 3‘d1; /* 消抖1 */
localparam KEY_h_1 = 3‘d2; /* 检测第一列 */
localparam KEY_h_2 = 3‘d3; /* 检测第二列 */
localparam KEY_h_3 = 3‘d4; /* 检测第三列 */
localparam KEY_h_4 = 3‘d5; /* 检测第四列 */
localparam KEY_pressed = 3‘d6; /* 按键值输出*/
localparam key_shake_2 = 3‘d7; /* 消抖2 */
/* 3-1 */
reg [2:0] current_state;
reg [2:0] next_state;
reg key_pressed_flag;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
begin
current_state <= 0;
end
else if(shake_over)
begin
current_state <= next_state;
end
else
current_state <= current_state ;
end
/* 3-2 */
always @(*)
begin
next_state = NO_KEY_pressed;
case(current_state)
NO_KEY_pressed:
begin
if(l_in != 4‘hf) next_state = key_shake_1;
else next_state = NO_KEY_pressed;
end
key_shake_1:
begin
if(l_in != 4‘hf) next_state = KEY_h_1;
else next_state = NO_KEY_pressed;
end
KEY_h_1:
begin
if(l_in != 4‘hf) next_state = KEY_pressed;
else next_state = KEY_h_2;
end
KEY_h_2:
begin
if(l_in != 4‘hf) next_state = KEY_pressed;
else next_state = KEY_h_3;
end
KEY_h_3:
begin
if(l_in != 4‘hf) next_state = KEY_pressed;
else next_state = KEY_h_4;
end
KEY_h_4:
begin
if(l_in != 4‘hf) next_state = KEY_pressed;
else next_state = NO_KEY_pressed;
end
KEY_pressed:
begin
if(l_in != 4‘hf) next_state = key_shake_2;
else next_state = NO_KEY_pressed;
end
key_shake_2:
begin
if(l_in != 4‘hf) next_state = key_shake_2;
else next_state = NO_KEY_pressed;
end
default:;
endcase
end
/* 3-3 */
reg [3:0] l_in_reg;
reg [3:0] h_out_reg;
reg [3:0] h_out;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
begin
l_in_reg <= 4‘d0;
h_out_reg<= 4‘d0;
h_out <= 4‘d0;
key_pressed_flag <= 0;
end
else if(shake_over)
begin
case(next_state)
NO_KEY_pressed:
begin
l_in_reg <= l_in_reg;
h_out_reg<= h_out_reg;
h_out <= 4‘d0;
key_pressed_flag <= 0;
end
// key_shake_1: begin end
KEY_h_1:
begin
h_out <= 4‘b0111;
end
KEY_h_2:
begin
h_out <= 4‘b1011;
end
KEY_h_3:
begin
h_out <= 4‘b1101;
end
KEY_h_4:
begin
h_out <= 4‘b1110;
end
KEY_pressed:
begin
l_in_reg <= l_in;
h_out_reg<= h_out;
end
key_shake_2: begin key_pressed_flag <= 1; end
default:;
endcase
end
end
reg [3:0] temp_key_val;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
temp_key_val <= 4‘d0;
else
begin
if(key_pressed_flag)
begin
case ({h_out_reg,l_in_reg})
8‘b0111_0111 : temp_key_val <= 4‘d0;
8‘b0111_1011 : temp_key_val <= 4‘d1;
8‘b0111_1101 : temp_key_val <= 4‘d2;
8‘b0111_1110 : temp_key_val <= 4‘d3;
8‘b1011_0111 : temp_key_val <= 4‘d4;
8‘b1011_1011 : temp_key_val <= 4‘d5;
8‘b1011_1101 : temp_key_val <= 4‘d6;
8‘b1011_1110 : temp_key_val <= 4‘d7;
8‘b1101_0111 : temp_key_val <= 4‘d8;
8‘b1101_1011 : temp_key_val <= 4‘d9;
8‘b1101_1101 : temp_key_val <= 4‘d10;
8‘b1101_1110 : temp_key_val <= 4‘d11;
8‘b1110_0111 : temp_key_val <= 4‘d12;
8‘b1110_1011 : temp_key_val <= 4‘d13;
8‘b1110_1101 : temp_key_val <= 4‘d14;
8‘b1110_1110 : temp_key_val <= 4‘d15;
default: temp_key_val <= 4‘d0;
endcase
end
end
end
assign key_val = temp_key_val;
assign key_val_flag = key_pressed_flag;
endmodule
测试代码：
module testbench;
reg clk; /* clk = 24M */
reg rst_n;
reg [3:0] l_in; //列输入，一般接上拉，为高电平
wire test_1;
wire test_2;
wire [3:0] h_out; //行输出信号，低有效
wire [3:0] key_val; //按键值，输出
wire key_val_flag;
keyboard u1(
.clk,
.rst_n,
.l_in,
.h_out,
.test_1,
.test_2,
.key_val,
.key_val_flag
);
parameter tck = 100;
parameter t = 1000/tck;
always
#(t/2) clk = ~clk;
task key_test;
input [3:0] data_key;
begin
#(3*t) l_in = data_key;
#(200*t) l_in = 4‘b1111;
#(50*t);
end
endtask
initial
begin
clk = 0;
rst_n = 0;
l_in = 4‘d0;
#(6*t) rst_n = 1;
key_test(4‘B1101);
key_test(4‘B0111);
end
endmodule
仿真波形：
时间： 2024-08-09 14:22:45