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: 2015.6
*******************************************************************************/ 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 [:] l_in; //列输入，一般接上拉，为高电平 output test_1;
output test_2; output [:] h_out; //行输出信号，低有效
output [:] key_val; //按键值，输出
output key_val_flag; wire [:] key_val;
reg test_1;
reg test_2;
//*************************************
/* 分频Ƶ*20ms，用于消抖 .状态机直接用clk_20ms，则可以跳过消抖*/ // `define CLK_24M
`define CLK_20M `ifdef CLK_24M
parameter t_20ms = 'd479999;
`endif `ifdef CLK_20M
parameter t_20ms = 'd399999;
`endif reg [:] 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 = 'd0; /* 初始化 */
localparam key_shake_1 = 'd1; /* 消抖1 */
localparam KEY_h_1 = 'd2; /* 检测第一列 */
localparam KEY_h_2 = 'd3; /* 检测第二列 */
localparam KEY_h_3 = 'd4; /* 检测第三列 */
localparam KEY_h_4 = 'd5; /* 检测第四列 */
localparam KEY_pressed = 'd6; /* 按键值输出*/
localparam key_shake_2 = 'd7; /* 消抖2 */ /* 3-1 */
reg [:] current_state;
reg [:] next_state;
reg key_pressed_flag;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
begin
current_state <= ;
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 != 'hf) next_state = key_shake_1;
else next_state = NO_KEY_pressed;
end
key_shake_1:
begin
if(l_in != 'hf) next_state = KEY_h_1;
else next_state = NO_KEY_pressed;
end
KEY_h_1:
begin
if(l_in != 'hf) next_state = KEY_pressed;
else next_state = KEY_h_2;
end
KEY_h_2:
begin
if(l_in != 'hf) next_state = KEY_pressed;
else next_state = KEY_h_3;
end
KEY_h_3:
begin
if(l_in != 'hf) next_state = KEY_pressed;
else next_state = KEY_h_4;
end
KEY_h_4:
begin
if(l_in != 'hf) next_state = KEY_pressed;
else next_state = NO_KEY_pressed;
end
KEY_pressed:
begin
if(l_in != 'hf) next_state = key_shake_2;
else next_state = NO_KEY_pressed;
end
key_shake_2:
begin
if(l_in != 'hf) next_state = key_shake_2;
else next_state = NO_KEY_pressed;
end
default:;
endcase
end /* 3-3 */ reg [:] l_in_reg;
reg [:] h_out_reg;
reg [:] h_out;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
begin
l_in_reg <= 'd0;
h_out_reg<= 'd0;
h_out <= 'd0;
key_pressed_flag <= ;
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 <= 'd0;
key_pressed_flag <= ;
end
KEY_h_1:
begin
h_out <= 'b1110;
end
KEY_h_2:
begin
h_out <= 'b1101;
end
KEY_h_3:
begin
h_out <= 'b1011;
end
KEY_h_4:
begin
h_out <= 'b0111;
end KEY_pressed:
begin
l_in_reg <= l_in;
h_out_reg<= h_out;
end
key_shake_2: begin key_pressed_flag <= ; end
default:;
endcase
end
end reg [:] temp_key_val;
always @(posedge clk or negedge rst_n)
begin
if(!rst_n)
temp_key_val <= 'd0;
else
begin
if(key_pressed_flag)
begin
case ({h_out_reg,l_in_reg})
'b1110_1110 : temp_key_val <= 4'd0;
'b1110_1101 : temp_key_val <= 4'd1;
'b1110_1011 : temp_key_val <= 4'd2;
'b1110_0111 : temp_key_val <= 4'd3; 'b1101_1110 : temp_key_val <= 4'd4;
'b1101_1101 : temp_key_val <= 4'd5;
'b1101_1011 : temp_key_val <= 4'd6;
'b1101_0111 : temp_key_val <= 4'd7; 'b1011_1110 : temp_key_val <= 4'd8;
'b1011_1101 : temp_key_val <= 4'd9;
'b1011_1011 : temp_key_val <= 4'd10;
'b1011_0111 : temp_key_val <= 4'd11; 'b0111_1110 : temp_key_val <= 4'd12;
'b0111_1101 : temp_key_val <= 4'd13;
'b0111_1011 : temp_key_val <= 4'd14;
'b0111_0111 : temp_key_val <= 4'd15; default: temp_key_val <= '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 [:] l_in; //列输入，一般接上拉，为高电平 wire test_1;
wire test_2; wire [:] h_out; //行输出信号，低有效
wire [:] 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
);
defparam u1. t_20ms = ; parameter tck = ;
parameter t = /tck; always
#(t/) clk = ~clk; task key_test;
input [:] data_key;
begin
#(*t) l_in = data_key;
#(*t) l_in = 'b1111;
#(*t);
end
endtask initial
begin
clk = ;
rst_n = ;
l_in = 'd0; #(*t) rst_n = ; #(*t);
key_test('B1101);
key_test('B1011); end endmodule
仿真波形：
