键盘扫描程序 FPGA

原文地址：FPGA">键盘扫描程序 FPGA作者：luqiang200006

    下面是一个4*4的矩阵键盘，是我们老师为了给我们练手而买的，今天上午老师让我们编写了键盘扫描程序，并用板上的LED显示出来。这里有三个程序，前面两个是别人写的，后面一个是我自己写的。

 

网上下的程序如下：

module key
  (clk,  //50MHZ
   reset,
  row,   //行
  col,   //列
   key_value //键值
   );
input clk,reset;
input [3:0] row;
output [3:0] col;
output [3:0] key_value;
reg [3:0] col;
reg [3:0] key_value;
reg [5:0] count;//delay_20ms
reg [2:0] state;  //状态标志
reg key_flag;   //按键标志位
reg clk_500khz;  //500KHZ时钟信号
reg [3:0] col_reg;  //寄存扫描列值
reg [3:0] row_reg;  //寄存扫描行值

always @(posedge clk or negedge reset)
if(!reset) begin clk_500khz<=0;count<=0; end
else
begin
if(count>=50) beginclk_500khz<=~clk_500khz;count<=0;end
else count<=count+1;
end

always @(posedge clk_500khz or negedge reset)
if(!reset) begincol<=4'b0000;state<=0;end
else
begin
case (state)
0:
 begin
col[3:0]<=4'b0000;
key_flag<=1'b0;
if(row[3:0]!=4'b1111) beginstate<=1;col[3:0]<=4'b1110;end//有键按下，扫描第一行
else state<=0;
end
1: 
begin
if(row[3:0]!=4'b1111) beginstate<=5;end  //判断是否是第一行
else  beginstate<=2;col[3:0]<=4'b1101;end //扫描第二行
end
2:
begin   
if(row[3:0]!=4'b1111) beginstate<=5;end   //判断是否是第二行
else  beginstate<=3;col[3:0]<=4'b1011;end //扫描第三行
end
3:
begin   
if(row[3:0]!=4'b1111) beginstate<=5;end  //判断是否是第三一行
else  beginstate<=4;col[3:0]<=4'b0111;end //扫描第四行
end
4:
begin   
if(row[3:0]!=4'b1111) beginstate<=5;end  //判断是否是第一行
else  state<=0;
end
5:
begin 
if(row[3:0]!=4'b1111)
begin
col_reg<=col;  //保存扫描列值
row_reg<=row;  //保存扫描行值
state<=5;
key_flag<=1'b1;  //有键按下
end            
else
begin state<=0;end
end   
endcase
end          

always @(clk_500khz or col_reg or row_reg)
begin
if(key_flag==1'b1)
begin
case ({col_reg,row_reg})
8'b1110_1110:key_value<=0;
8'b1110_1101:key_value<=1;
8'b1110_1011:key_value<=2;
8'b1110_0111:key_value<=3;
8'b1101_1110:key_value<=4;
8'b1101_1101:key_value<=5;
8'b1101_1011:key_value<=6;
8'b1101_0111:key_value<=7;
8'b1011_1110:key_value<=8;
8'b1011_1101:key_value<=9;
8'b1011_1011:key_value<=10;
8'b1011_0111:key_value<=11;
8'b0111_1110:key_value<=12;
8'b0111_1101:key_value<=13;
8'b0111_1011:key_value<=14;
8'b0111_0111:key_value<=15;    
endcase
end  
end      
endmodule

 

另一个程序，和上面的思想一样：

 

module key44

(

      code     ,

      col      ,

      valid    ,

      row      ,

      sys_clk   ,

      rst 

);

 

//-------------------------------------------------------------------------------------------------

// Port declaration

output  [3:0] col    ;

output        valid   ;

output  [3:0] code    ;

 

input  [3:0] row    ;

input         sys_clk,rst;

 

//-------------------------------------------------------------------------------------------------

//

reg    [3:0]  col,code;

reg    [5:0]  state,next_state;

 

parameter  S_0 = 6'b000001,

          S_1 = 6'b000010,

          S_2 = 6'b000100,

          S_3 = 6'b001000,

          S_4 = 6'b010000,

          S_5 = 6'b100000;

reg       S_row ;

reg [3:0] count,row_reg,col_reg;

reg      clk2,clk4;

 

 

reg [4:0] Mega_cnt;

wire     clk;

 

always @( posedge sys_clk, negedge rst )

begin

      if(!rst)      Mega_cnt<=0;

      else       Mega_cnt<=Mega_cnt+1;

end

 

assign clk = Mega_cnt[4];

 

// Frequency Division Two

always @( posedge clk )

clk2 <= ~clk2;

 

// A quarter of the clk

always @( posedge clk2 )

clk4 <= ~clk4;

 

always @( posedge clk4, negedge rst )

if(!rst)

      begin

             count <= 0;

             S_row <= 0;

      end

else

      begin

            if(!(row[0]&row[1]&row[2]&row[3]))

                   begin

                          if(count < 'd4)  count<= count +1;           // Filter

                          else              S_row <= 1;

                   end

             else if((state == S_0) || (state == S_5))

                   begin

                          count <= 0;

                          S_row <= 0;

                   end

      end

 

assign valid = ((state == S_1)||(state == S_2)||(state ==S_3)||(state == S_4))&& (!(row[3]&row[2]&row[1]&row[0]));

 

// Save the value of row and col

always @( negedge clk )

if( valid )

      begin

            row_reg <= row ;

            col_reg <= col ;

      end

 

// Decode the Key

always @( row_reg, col_reg, clk )

      case( {row_reg,col_reg} )

            8'B1110_1110: code = 4'hd;

            8'B1110_1101: code = 4'h9;

            8'B1110_1011: code = 4'h5;

            8'B1110_0111: code = 4'h1;

             

            8'B1101_1110: code = 4'he;

            8'B1101_1101: code = 4'ha;

            8'B1101_1011: code = 4'h6;

            8'B1101_0111: code = 4'h2;

             

            8'B1011_1110: code = 4'hf;

            8'B1011_1101: code = 4'hb;

            8'B1011_1011: code = 4'h7;

            8'B1011_0111: code = 4'h3;

             

            8'B0111_1110: code = 4'h0;

            8'B0111_1101: code = 4'hc;

            8'B0111_1011: code = 4'h8;

            8'B0111_0111: code = 4'h4;

             default             : code = 4'h0;

      endcase

 

always @( posedge clk4, negedge rst )

      if( !rst )

             state <= S_0 ;

      else

             state <= next_state ;

 

always @( state, row, S_row )

begin

      col = 0;

      // Decoding...

      S_1 :  begin

                   col = 4'b1110;

                   if(row!='hf)      next_state = S_5;

                   else              next_state = S_2;

             end

      S_2 :  begin

                   col = 4'b1101;

                   if(row!='hf)      next_state = S_5;

                   else              next_state = S_3;

             end

      S_3 :  begin

                   col = 4'b1011;

                   if(row!='hf)      next_state = S_5;

                   else              next_state = S_4;

             end 

      S_4 :  begin

                   col = 4'b0111;

                   if(row!='hf)      next_state = S_5;

                   else              next_state = S_0;

             end 

      //----------------------------------------------

      S_5 :  begin

                   col = 4'b0000;

                   if(row == 4'b1111)      next_state = S_0;

                   else                         next_state = S_5;

             end

      default: next_state = S_0;

      endcase

end

endmodule 

 

下面是我自己写的一个程序：

module Key_led(clk,row,col,key_temp);
input clk,row;
output key_temp,col;
reg[3:0]key_temp;                                    //key temporary value
reg[3:0] col;
wire[3:0] row;
reg key_down , clk_100;
reg[1:0] key_curstate ,key_nexstate;
integer cont;

always @(posedge clk)
begin
if(cont==500000) cont=1;
else cont=cont+1;
if(cont==1) clk_100=1;
else clk_100=0;
end                                   

initial begin
key_curstate=2'b00;
end

always @(posedge clk_100)
begin
if(row!=4'b1111) key_down=1;
else key_down=0;
end

always @(posedge clk_100)
begin
col=4'b0000;
case(key_curstate)
00:begin
if(key_down==0) key_nexstate=00;
else key_nexstate=10;
end
10:begin
if(key_down==0) key_nexstate=01;
else key_nexstate=11;
end
11:begin
if(key_down==0) key_nexstate=01;
else key_nexstate=11;
end
01:begin
if(key_down==0) key_nexstate=00;
else key_nexstate=10;
end
endcase
if(key_curstate==2'b11)begin
col=4'b0111;
  if(row==4'b0111) key_temp=4'h0;
  else if(row==4'b1011) key_temp=4'h4;
  else if(row==4'b1101) key_temp=4'h8;
  else if(row==4'b1110) key_temp=4'hc;
  else begin
   col=4'b1011;
   if(row==4'b0111) key_temp=4'h1;
    elseif(row==4'b1011) key_temp=4'h5;
    elseif(row==4'b1101) key_temp=4'h9;
    elseif(row==4'b1110) key_temp=4'hd;
    elsebegin
     col=4'b1101;
     if(row==4'b0111) key_temp=4'h2;
     else if(row==4'b1011) key_temp=4'h6;
     else if(row==4'b1101) key_temp=4'ha;
     else if(row==4'b1110) key_temp=4'he;
     else begin
        col=4'b1110;
        if(row==4'b0111) key_temp=4'h3;
        else if(row==4'b1011) key_temp=4'h7;
        else if(row==4'b1101) key_temp=4'hb;
        else if(row==4'b1110) key_temp=4'hf;
      end
    end
   end
  end
end

 

always @(posedge clk_100)

key_curstate=key_nexstate;

endmodule