Verilog 交通灯控制器设计：十字路口倒计时显示

以下是一个可能的 Verilog 代码实现：

module traffic_light_controller( input clk, input reset, output reg [2:0] east_west_led, // 东西方向灯 output reg [2:0] north_south_led, // 南北方向灯 output reg [15:0] countdown // 倒计时数码管 );

// 状态定义 parameter [1:0] IDLE = 2'b00; parameter [1:0] GREEN = 2'b01; parameter [1:0] YELLOW = 2'b10; parameter [1:0] RED = 2'b11;

// 时序参数定义 parameter GREEN_TIME = 5; // 绿灯时间 parameter YELLOW_TIME = 3; // 黄灯时间 parameter RED_TIME = 8; // 红灯时间

// 内部状态定义 reg [1:0] east_west_state, north_south_state; // 东西/南北方向的灯状态 reg [3:0] east_west_timer, north_south_timer; // 东西/南北方向的定时器 reg [1:0] east_west_output, north_south_output; // 东西/南北方向的输出状态

// 倒计时数码管显示 reg [2:0] countdown_sec; // 倒计时秒数 reg [1:0] countdown_unit; // 倒计时单位（0：绿灯，1：黄灯，2：红灯） always @ (posedge clk) begin if (reset) begin countdown <= 16'h0000; countdown_sec <= 4'd0; countdown_unit <= 2'b00; end else begin if (north_south_state == GREEN) begin countdown_sec <= north_south_timer; countdown_unit <= 2'b00; end else if (north_south_state == YELLOW) begin countdown_sec <= north_south_timer - GREEN_TIME; countdown_unit <= 2'b01; end else if (north_south_state == RED) begin countdown_sec <= north_south_timer - GREEN_TIME - YELLOW_TIME; countdown_unit <= 2'b10; end countdown <= {countdown_unit, countdown_sec}; end end

// 东西方向的状态机 always @ (posedge clk) begin if (reset) begin east_west_state <= IDLE; east_west_timer <= 4'd0; east_west_output <= 3'b000; end else begin case (east_west_state) IDLE: begin east_west_timer <= GREEN_TIME; east_west_output <= 3'b001; // 绿灯 east_west_state <= GREEN; end GREEN: begin if (east_west_timer == 0) begin east_west_timer <= YELLOW_TIME; east_west_output <= 3'b010; // 黄灯 east_west_state <= YELLOW; end else begin east_west_timer <= east_west_timer - 1; end end YELLOW: begin if (east_west_timer == 0) begin east_west_timer <= RED_TIME; east_west_output <= 3'b100; // 红灯 east_west_state <= RED; end else begin east_west_timer <= east_west_timer - 1; end end RED: begin if (east_west_timer == 0) begin east_west_timer <= GREEN_TIME; east_west_output <= 3'b001; // 绿灯 east_west_state <= GREEN; end else begin east_west_timer <= east_west_timer - 1; end end endcase end end

// 南北方向的状态机，和东西方向的类似 always @ (posedge clk) begin if (reset) begin north_south_state <= RED; north_south_timer <= RED_TIME; north_south_output <= 3'b100; // 南北方向一开始是红灯 end else begin case (north_south_state) IDLE: begin north_south_timer <= GREEN_TIME; north_south_output <= 3'b100; // 红灯 north_south_state <= RED; end GREEN: begin if (north_south_timer == 0) begin north_south_timer <= YELLOW_TIME; north_south_output <= 3'b010; // 黄灯 north_south_state <= YELLOW; end else begin north_south_timer <= north_south_timer - 1; end end YELLOW: begin if (north_south_timer == 0) begin north_south_timer <= RED_TIME; north_south_output <= 3'b001; // 绿灯 north_south_state <= RED; end else begin north_south_timer <= north_south_timer - 1; end end RED: begin if (north_south_timer == 0) begin north_south_timer <= GREEN_TIME; north_south_output <= 3'b100; // 红灯 north_south_state <= GREEN; end else begin north_south_timer <= north_south_timer - 1; end end endcase end end

// 输出灯的状态 assign east_west_led = east_west_output; assign north_south_led = north_south_output;

endmodule

该模块包含两个状态机，分别控制东西方向和南北方向的交通灯。状态机的实现比较简单，主要是根据当前状态和计时器值来控制输出灯的状态，并在定时器倒计时结束时切换状态。同时，倒计时数码管的显示也需要在时钟上升沿时更新，根据当前状态和计时器值来计算剩余时间和当前所处的灯颜色。