define SCAN
module key_scan(
clk ,
rst_n ,
key_col, //键盘列输入
key_row, //键盘行输出
key_num, //指示哪一个按键按下，用0~15指示
key_vld //按下有用指示信号，其为1表明按下一次。
);
parameter KEY_W = 4 ;
parameter COL = 0 ;
parameter ROW = 1 ;
parameter DLY = 2 ;
parameter FIN = 3 ;
parameter COL_CNT = 16;
parameter TIME_20MS= 1000000;
//输入信号界说
input clk ;
input rst_n ;
input [3:0] key_col;
//输出信号界说
output key_vld;
output[3:0] key_num;
output[KEY_W-1:0] key_row;
//输出信号reg界说
reg [3:0] key_num;
reg [KEY_W-1:0] key_row;
reg key_vld;
reg [ 3:0] key_col_ff0 ;
reg [ 3:0] key_col_ff1 ;
reg [ 1:0] key_col_get ;
reg shake_flag ;
reg shake_flag_ff0;
reg [ 3:0] state_c ;
reg [19:0] shake_cnt ;
reg [ 3:0] state_n ;
reg [ 1:0] row_index ;
reg [15:0] row_cnt ;
reg [ 2:0] x ;
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_col_ff0 <= 4'b1111;
key_col_ff1 <= 4'b1111;
end
else begin
key_col_ff0 <= key_col ;
key_col_ff1 <= key_col_ff0;
end
end
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
shake_cnt <= 0;
end
else if(add_shake_cnt)begin
if(end_shake_cnt)
shake_cnt <= 0;
else
shake_cnt <= shake_cnt + 1;
end
else begin
shake_cnt <= 0;
end
end
assign add_shake_cnt = key_col_ff1!=4'hf && shake_flag==0;
assign end_shake_cnt = add_shake_cnt && shake_cnt==TIME_20MS-1;
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
shake_flag <= 0;
end
else if(end_shake_cnt) begin
shake_flag <= 1'b1;
end
else if(key_col_ff1==4'hf) begin
shake_flag <= 1'b0;
end
end
`ifdef SCAN
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
state_c <= COL;
end
else begin
state_c <= state_n;
end
end
always @(*)begin
case(state_c)
COL: begin
if(col2row_start)begin
state_n = ROW;
end
else begin
state_n = state_c;
end
end
ROW: begin
if(row2dly_start)begin
state_n = DLY;
end
else begin
state_n = state_c;
end
end
DLY : begin
if(dly2fin_start)begin
state_n = FIN;
end
else begin
state_n = state_c;
end
end
FIN: begin
if(fin2col_start)begin
state_n = COL;
end
else begin
state_n = state_c;
end
end
default: state_n = COL;
endcase
end
assign col2row_start = state_c==COL && end_shake_cnt;
assign row2dly_start = state_c==ROW && end_row_index;
assign dly2fin_start = state_c==DLY && end_row_index;
assign fin2col_start = state_c==FIN && key_col_ff1==4'hf;
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_row <= 4'b0;
end
else if(state_c==ROW)begin
key_row <= ~(1'b1 << row_index);
end
else begin
key_row <= 4'b0;
end
end
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
row_cnt <= 0;
end
else if(add_row_cnt) begin
if(end_row_cnt)
row_cnt <= 0;
else
row_cnt <= row_cnt + 1;
end
end
assign add_row_cnt = state_c==ROW || state_c==DLY;
assign end_row_cnt = add_row_cnt && row_cnt==COL_CNT-1;
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
row_index <= 0;
end
else if(add_row_index) begin
if(end_row_index)
row_index <= 0;
else
row_index <= row_index + 1;
end
end
assign add_row_index = end_row_cnt;
assign end_row_index = add_row_index && row_index==x-1;
always @(*)begin
if(state_c==ROW)
x = 4;
else
x = 1;
end
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_col_get <= 0;
end
else if(col2row_start) begin
if(key_col_ff1==4'b1110)
key_col_get <= 0;
else if(key_col_ff1==4'b1101)
key_col_get <= 1;
else if(key_col_ff1==4'b1011)
key_col_get <= 2;
else
key_col_get <= 3;
end
end
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_num <= 0;
end
else if(state_c==ROW && end_row_cnt)begin
key_num <= {row_index,key_col_get};
end
else begin
key_num <= 0;
end
end
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_vld <= 1'b0;
end
else if(state_c==ROW && end_row_cnt && key_col_ff1[key_col_get]==1'b0)begin
key_vld <= 1'b1;
end
else begin
key_vld <= 1'b0;
end
end
`else
always @(posedge clk or negedge rst_n)begin
if(rst_n==1'b0)begin
key_vld <= 0;
end
else begin
key_vld <= end_shake_cnt;
end
end
always @(*)begin
key_num = 0;
end
`endif
endmodule
