通过按键控制蜂鸣器工作。

模块框图：

时序图：

代码：

/*1位按键消抖
*/ 
module key_filter (input       wire            sys_clk     ,input       wire            sys_rst_n   ,input       wire            key_in      ,output      reg             key_flag    
);// 参数定义parameter   MAX_CNT_10MS = 500_000  ;localparam  IDLE        = 4'b0001   ,FILTER_UP   = 4'b0010   ,SAMPLING    = 4'b0100   ,FILTER_BACK = 4'b1000   ;// reg signal define reg                 key_in_r1 ;  reg                 key_in_r2 ;reg     [18:0]      cnt_core  ;reg     [3:0]       state_c   ;reg     [3:0]       state_n   ;// wire signal define wire                nege      ;wire                pose      ;wire                IDLEtoFILTER_UP       ;wire                FILTER_UPtoIDLE       ;wire                FILTER_UPtoSAMPLING   ;wire                SAMPLINGtoFILTER_BACK ;wire                FILTER_BACKtoIDLE     ;wire                filter_done           ; /******************************************************************/// reg                 key_in_r1 ; always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) key_in_r1 <= 1'b1 ;elsekey_in_r1 <= key_in ;end // reg                 key_in_r2 ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) key_in_r2 <= 1'b1 ;elsekey_in_r2 <= key_in_r1 ;end // wire                nege      ;assign  nege = ~key_in_r1 &&  key_in_r2 ;// wire                pose      ;  assign  pose =  key_in_r1 && ~key_in_r2 ;// reg     [3:0]       state_c   ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) state_c <= IDLE ;elsestate_c <= state_n ;end// reg     [3:0]       state_n   ;always @(*) begincase(state_c)IDLE      : if(IDLEtoFILTER_UP)state_n = FILTER_UP ;else state_n = IDLE ;FILTER_UP : if(FILTER_UPtoIDLE)state_n = IDLE ;else if(FILTER_UPtoSAMPLING)state_n = SAMPLING ;else state_n = FILTER_UP ;SAMPLING  : if(SAMPLINGtoFILTER_BACK)state_n = FILTER_BACK ;else state_n = SAMPLING ;FILTER_BACK:if(FILTER_BACKtoIDLE)state_n = IDLE ;elsestate_n = FILTER_BACK ;default   :     state_n = IDLE ;endcaseendassign  IDLEtoFILTER_UP         = (state_c == IDLE)       && (nege) ;assign  FILTER_UPtoIDLE         = (state_c == FILTER_UP)  && (pose) ;assign  FILTER_UPtoSAMPLING     = (state_c == FILTER_UP)  && (filter_done) ;assign  SAMPLINGtoFILTER_BACK   = (state_c == SAMPLING)   && (pose) ;assign  FILTER_BACKtoIDLE       = (state_c == FILTER_BACK)&& (filter_done) ;// reg     [18:0]      cnt_core  ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) cnt_core <= 19'd0 ;elsecase (state_c)IDLE       :cnt_core <= 19'd0 ; FILTER_UP  :if(filter_done)cnt_core <= 19'd0 ;else cnt_core <= cnt_core + 1'b1 ;SAMPLING   :cnt_core <= 19'd0 ; FILTER_BACK:if(filter_done)cnt_core <= 19'd0 ;else cnt_core <= cnt_core + 1'b1 ;default    :    cnt_core <= 19'd0 ;endcaseend// wire                filter_doneassign  filter_done = (cnt_core == MAX_CNT_10MS - 1) ;// output reg key_flagalways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) key_flag <= 1'b0 ;else if(FILTER_UPtoSAMPLING)key_flag <= ~key_in_r2 ;else key_flag <= 1'b0 ;endendmodule

/*蜂鸣器驱动模块，NPN三极管，beep_en == 1 鸣叫。有源电磁式。1， 初始状态鸣叫，按键每按下一次，蜂鸣器状态翻转。2.  初始状态蜂鸣器工作，响100ms , 不响100ms, 响100ms, 不响300ms.按键每按下一次，蜂鸣器工作状态翻转。
*/ 
module beep (input       wire            sys_clk     ,input       wire            sys_rst_n   ,input       wire            key_flag    ,output      reg             beep_en     
);// // output reg beep_en// always @(posedge sys_clk or negedge sys_rst_n) begin//     if(~sys_rst_n) //         beep_en <= 1'b1 ;//     else if(key_flag)//         beep_en <= ~beep_en ;// end// parameterparameter   MAX_CNT_100MS = 5_000_000  ,MAX_CNT_300MS = 15_000_000 ;localparam  RING          = 3'b001     ,NO_RING_MOD1  = 3'b010     ,NO_RING_MOD2  = 3'b100     ;// reg signal definereg                 beep_work ;reg     [23:0]      cnt_core  ;reg     [2:0]       state_c   ;reg     [2:0]       state_n   ;reg                 mod1_flag ;// wire signal definewire                RINGtoNO_RING_MOD1 ;wire                RINGtoNO_RING_MOD2 ;wire                NO_RING_MOD1toRING ;wire                NO_RING_MOD2toRING ;wire                no_ring_done       ;/*****************************************************/// reg                 beep_work ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beep_work <= 1'b1 ;else if(key_flag)beep_work <= ~beep_work ;else beep_work <= beep_work ;end// reg     [2:0]       state_c   ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) state_c <= RING ;else state_c <= state_n ;end// reg     [2:0]       state_n   ;always @(*) beginif(beep_work) begincase(state_c)RING        :   if(RINGtoNO_RING_MOD1)state_n = NO_RING_MOD1 ;else if(RINGtoNO_RING_MOD2)state_n = NO_RING_MOD2 ;elsestate_n = RING ;NO_RING_MOD1:   if(NO_RING_MOD1toRING)state_n = RING ;else state_n = NO_RING_MOD1 ;NO_RING_MOD2:   if(NO_RING_MOD2toRING)state_n = RING ;else state_n = NO_RING_MOD2 ;default     :       state_n = RING ;endcaseendelsestate_n = RING ;endassign  RINGtoNO_RING_MOD1 = (state_c == RING)         && (no_ring_done && (mod1_flag))    ;assign  RINGtoNO_RING_MOD2 = (state_c == RING)         && (no_ring_done && (!mod1_flag))   ;assign  NO_RING_MOD1toRING = (state_c == NO_RING_MOD1) && (no_ring_done) ;assign  NO_RING_MOD2toRING = (state_c == NO_RING_MOD2) && (no_ring_done) ;// reg     [23:0]      cnt_core  ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) cnt_core <= 24'd0 ;elseif(beep_work) begincase (state_c)RING        :   if(no_ring_done)cnt_core <= 24'd0 ;else cnt_core <= cnt_core + 1'b1 ; NO_RING_MOD1:   if(no_ring_done)cnt_core <= 24'd0 ;else cnt_core <= cnt_core + 1'b1 ; NO_RING_MOD2:   if(no_ring_done)cnt_core <= 24'd0 ;else cnt_core <= cnt_core + 1'b1 ;  default     :   cnt_core <= 24'd0 ;endcaseendelse cnt_core <= 24'd0 ;end// reg                 mod1_flag ;always @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) mod1_flag <= 1'b1 ;else if(beep_work) beginif((state_c != RING) && (no_ring_done))mod1_flag <= ~mod1_flag ;else mod1_flag <= mod1_flag ;endelse mod1_flag <= 1'b1 ;end// wire                no_ring_done;assign  no_ring_done = (((state_c != NO_RING_MOD2)&&(cnt_core == MAX_CNT_100MS - 1))||((state_c == NO_RING_MOD2)&&(cnt_core == MAX_CNT_300MS - 1))) ? 1'b1 : 1'b0 ;// output reg beep_enalways @(posedge sys_clk or negedge sys_rst_n) beginif(~sys_rst_n) beep_en <= 1'b1 ;else if(beep_work) beginif(state_c == RING)beep_en <= 1'b1 ;else beep_en <= 1'b0 ;endelse beep_en <= 1'b0 ; endendmodule

module top(input       wire            sys_clk     ,input       wire            sys_rst_n   ,input       wire            key_in      ,output      wire            beep        
);// 例化间连线wire        key_flag ;
key_filter key_filter_inst(.sys_clk                ( sys_clk   ) ,.sys_rst_n              ( sys_rst_n ) ,.key_in                 ( key_in    ) ,.key_flag               ( key_flag  )  
);beep beep_inst(.sys_clk                ( sys_clk   ) ,.sys_rst_n              ( sys_rst_n ) ,.key_flag               ( key_flag  ) ,.beep_en                ( beep      )  
);endmodule

`timescale 1ns/1ns
module test_top();reg            sys_clk     ;reg            sys_rst_n   ;reg            key_in      ;wire           beep        ;top top_inst(.sys_clk        ( sys_clk   ) ,.sys_rst_n      ( sys_rst_n ) ,.key_in         ( key_in    ) ,.beep           ( beep      )  
);parameter   CYCLE = 20 ;defparam    top_inst.key_filter_inst.MAX_CNT_10MS = 50 ;defparam    top_inst.beep_inst.MAX_CNT_100MS = 500  ;defparam    top_inst.beep_inst.MAX_CNT_300MS = 1500 ;initial beginsys_clk    = 1'b1 ;sys_rst_n <= 1'b0 ;key_in    <= 1'b1 ;#( CYCLE * 10 )   ;sys_rst_n <= 1'b1 ;#( CYCLE * 10 )   ;#( CYCLE * 3000 ) ;#( CYCLE * 500  ) ; // 检测蜂鸣器状态机是否正常工作。key_in    <= 1'b0 ;#( CYCLE * 50 * 3 ); // 按下足够长的时间，第一次按键按下。key_in    <= 1'b1 ;#( CYCLE * 3000 ) ;#( CYCLE * 500  ) ; // 检测蜂鸣器状态机是否正常工作。key_in    <= 1'b0 ;#( CYCLE * 50 * 3 ); // 按下足够长的时间，第二次按键按下。key_in    <= 1'b1 ;#( CYCLE * 3000 ) ;#( CYCLE * 500  ) ; // 检测蜂鸣器状态机是否正常工作。$stop             ;endalways #( CYCLE / 2 ) sys_clk = ~sys_clk ;endmodule

仿真：