写一段可以控制三层电梯的verilog语言代码

以下是一个简单的控制三层电梯的Verilog语言代码，包括电梯的状态机和控制逻辑：

module elevator (
    input clk,
    input rst,
    input up_button,
    input down_button,
    input [2:0] floor_sensor,
    output reg [2:0] floor
);

// Define the states
parameter IDLE = 2'b00;
parameter MOVING_UP = 2'b01;
parameter MOVING_DOWN = 2'b10;

// Define the floor constants
parameter FLOOR_1 = 3'b000;
parameter FLOOR_2 = 3'b001;
parameter FLOOR_3 = 3'b010;

// Define the state and floor variables
reg [1:0] state;
reg [2:0] current_floor;

// Set the initial state and floor
initial begin
    state = IDLE;
    current_floor = FLOOR_1;
end

// Define the state machine
always @ (posedge clk or posedge rst) begin
    if (rst) begin
        state <= IDLE;
        current_floor <= FLOOR_1;
    end else begin
        case (state)
            IDLE: begin
                if (up_button && current_floor != FLOOR_3) begin
                    state <= MOVING_UP;
                end else if (down_button && current_floor != FLOOR_1) begin
                    state <= MOVING_DOWN;
                end
            end
            MOVING_UP: begin
                if (floor_sensor[current_floor+1]) begin
                    current_floor <= current_floor + 1;
                    state <= IDLE;
                end
            end
            MOVING_DOWN: begin
                if (floor_sensor[current_floor-1]) begin
                    current_floor <= current_floor - 1;
                    state <= IDLE;
                end
            end
        endcase
    end
end

// Set the floor output
always @ (current_floor) begin
    case (current_floor)
        FLOOR_1: floor = FLOOR_1;
        FLOOR_2: floor = FLOOR_2;
        FLOOR_3: floor = FLOOR_3;
    endcase
end

endmodule

该代码使用状态机模型控制电梯的状态，并根据输入的按钮和传感器信号来决定电梯的运动方向和停靠楼层。在每个时钟周期中，状态机会检查当前状态并执行相应的操作，例如启动电梯或将其停靠在所需的楼层。输出端口 floor 显示当前电梯所在的楼层。