三段式和二段式一段式状态机verilog实现

Verilog是一种硬件描述语言，可以用于实现状态机。下面是三段式、二段式和一段式状态机的Verilog实现示例：

## 三段式状态机

module Three_State_Machine (
    input clk,            // 时钟信号
    input reset,          // 复位信号
    input event,          // 事件信号
    output reg state_out  // 输出状态信号
);

// 定义状态枚举类型
typedef enum logic [1:0] {
    STATE_IDLE,
    STATE_WAIT_EVENT,
    STATE_PROCESS_EVENT
} state_type;

// 定义状态变量和状态转移条件
reg [1:0] state, next_state;
always @(*) begin
    case (state)
        STATE_IDLE: begin
            if (event) next_state = STATE_WAIT_EVENT;
            else next_state = STATE_IDLE;
        end
        STATE_WAIT_EVENT: begin
            next_state = STATE_PROCESS_EVENT;
        end
        STATE_PROCESS_EVENT: begin
            next_state = STATE_IDLE;
        end
        default: next_state = STATE_IDLE;
    endcase
end

// 状态机状态寄存器
always @(posedge clk, posedge reset) begin
    if (reset) state <= STATE_IDLE;
    else state <= next_state;
end

// 输出状态信号
always @(*) begin
    case (state)
        STATE_IDLE: state_out = 1'b0;
        STATE_WAIT_EVENT: state_out = 1'b1;
        STATE_PROCESS_EVENT: state_out = 1'b0;
        default: state_out = 1'b0;
    endcase
end

endmodule

## 二段式状态机

module Two_State_Machine (
    input clk,            // 时钟信号
    input reset,          // 复位信号
    input event,          // 事件信号
    output reg state_out  // 输出状态信号
);

// 定义状态枚举类型
typedef enum logic [0:0] {
    STATE_IDLE,
    STATE_PROCESS_EVENT
} state_type;

// 定义状态变量和状态转移条件
reg [0:0] state, next_state;
always @(*) begin
    case (state)
        STATE_IDLE: begin
            if (event) next_state = STATE_PROCESS_EVENT;
            else next_state = STATE_IDLE;
        end
        STATE_PROCESS_EVENT: begin
            next_state = STATE_IDLE;
        end
        default: next_state = STATE_IDLE;
    endcase
end

// 状态机状态寄存器
always @(posedge clk, posedge reset) begin
    if (reset) state <= STATE_IDLE;
    else state <= next_state;
end

// 输出状态信号
always @(*) begin
    case (state)
        STATE_IDLE: state_out = 1'b0;
        STATE_PROCESS_EVENT: state_out = 1'b1;
        default: state_out = 1'b0;
    endcase
end

endmodule

## 一段式状态机

module One_State_Machine (
    input clk,            // 时钟信号
    input reset,          // 复位信号
    input event,          // 事件信号
    output reg state_out  // 输出状态信号
);

// 定义状态枚举类型
typedef enum logic [0:0] {
    STATE_IDLE
} state_type;

// 定义状态变量和状态转移条件
reg [0:0] state, next_state;
always @(*) begin
    next_state = STATE_IDLE;
end

// 状态机状态寄存器
always @(posedge clk, posedge reset) begin
    if (reset) state <= STATE_IDLE;
    else state <= next_state;
end

// 输出状态信号
always @(*) begin
    case (state)
        STATE_IDLE: state_out = 1'b0;
        default: state_out = 1'b0;
    endcase
end

endmodule