帮我写一个FPGA秒表测试台，秒表共有六个数码管，分别指示小时，分钟，秒

好的，这里提供一个简单的FPGA秒表测试台的Verilog代码，使用FPGA板上的六个共阳数码管（CA0-CA5）来显示小时，分钟和秒数。同时，使用4个按键控制秒表的启动、停止、复位和调整。代码如下：

module stopwatch(
    input clk,   //时钟信号
    input rst,   //重置信号
    input start, //启动信号
    input stop,  //停止信号
    input reset, //复位信号
    input adjust, //调整信号
    output reg [5:0] CA0, //数码管0
    output reg [5:0] CA1, //数码管1
    output reg [5:0] CA2, //数码管2
    output reg [5:0] CA3, //数码管3
    output reg [5:0] CA4, //数码管4
    output reg [5:0] CA5  //数码管5
);

reg [23:0] cnt; //计数器
reg [2:0] sec; //秒数
reg [2:0] min; //分钟数
reg [1:0] hour; //小时数
reg [1:0] flag; //标志位，用于控制闪烁

//时钟分频，每秒计数器加1
always @(posedge clk or posedge rst) begin
    if(rst) begin
        cnt <= 0;
        sec <= 0;
        min <= 0;
        hour <= 0;
        flag <= 0;
    end else if(cnt == 49999999) begin
        cnt <= 0;
        sec <= sec + 1;
        if(sec == 60) begin
            sec <= 0;
            min <= min + 1;
            if(min == 60) begin
                min <= 0;
                hour <= hour + 1;
                if(hour == 24) begin
                    hour <= 0;
                end
            end
        end
    end else begin
        cnt <= cnt + 1;
    end
end

//数码管显示，使用分频后的秒数、分钟数和小时数
always @(posedge clk or posedge rst) begin
    if(rst) begin
        CA0 <= 6'b000000;
        CA1 <= 6'b000000;
        CA2 <= 6'b000000;
        CA3 <= 6'b000000;
        CA4 <= 6'b000000;
        CA5 <= 6'b000000;
    end else begin
        case(flag)
            2'b00: begin
                CA0 <= {7'b1111111-8'h3F, 8'h3F}[hour[1:0]];
                CA1 <= {7'b1111111-8'h7F, 8'h7F}[hour[1:0]];
                CA2 <= {7'b1111111-8'h3F, 8'h3F}[min[1:0]];
                CA3 <= {7'b1111111-8'h7F, 8'h7F}[min[1:0]];
                CA4 <= {7'b1111111-8'h3F, 8'h3F}[sec[1:0]];
                CA5 <= {7'b1111111-8'h7F, 8'h7F}[sec[1:0]];
            end
            2'b01: begin
                CA0 <= 6'b000000;
                CA1 <= {7'b1111111-8'h3F, 8'h3F}[hour[1:0]];
                CA2 <= 6'b000000;
                CA3 <= {7'b1111111-8'h3F, 8'h3F}[min[1:0]];
                CA4 <= 6'b000000;
                CA5 <= {7'b1111111-8'h3F, 8'h3F}[sec[1:0]];
            end
            2'b10: begin
                CA0 <= {7'b1111111-8'h3F, 8'h3F}[hour[1:0]];
                CA1 <= 6'b000000;
                CA2 <= {7'b1111111-8'h3F, 8'h3F}[min[1:0]];
                CA3 <= 6'b000000;
                CA4 <= {7'b1111111-8'h3F, 8'h3F}[sec[1:0]];
                CA5 <= 6'b000000;
            end
            default: begin
                CA0 <= 6'b000000;
                CA1 <= 6'b000000;
                CA2 <= 6'b000000;
                CA3 <= 6'b000000;
                CA4 <= 6'b000000;
                CA5 <= 6'b000000;
            end
        endcase
    end
end

//按键控制，使用状态机实现
reg [1:0] state; //状态机状态
always @(posedge clk or posedge rst) begin
    if(rst) begin
        state <= 2'b00;
    end else case(state)
        2'b00: begin //初始状态
            if(start) begin
                state <= 2'b01;
            end else if(reset) begin
                sec <= 0;
                min <= 0;
                hour <= 0;
            end
        end
        2'b01: begin //运行状态
            if(stop) begin
                state <= 2'b10;
            end else if(reset) begin
                sec <= 0;
                min <= 0;
                hour <= 0;
                state <= 2'b00;
            end else if(adjust) begin
                state <= 2'b11;
            end
        end
        2'b10: begin //停止状态
            if(start) begin
                state <= 2'b01;
            } else if(reset) begin
                sec <= 0;
                min <= 0;
                hour <= 0;
                state <= 2'b00;
            end else if(adjust) begin
                state <= 2'b11;
            end
        end
        2'b11: begin //调整状态
            if(!adjust) begin
                state <= 2'b01;
            end
        end
    endcase
end

//调整小时数、分钟数和秒数
always @(posedge clk or posedge rst) begin
    if(rst) begin
        flag <= 0;
    end else case(state)
        2'b11: begin //调整状态
            case(flag)
                2'b00: begin
                    if(adjust) begin
                        hour <= hour + 1;
                        if(hour == 24) begin
                            hour <= 0;
                        end
                    end
                end
                2'b01: begin
                    if(adjust) begin
                        min <= min + 1;
                        if(min == 60) begin
                            min <= 0;
                        end
                    end
                end
                2'b10: begin
                    if(adjust) begin
                        sec <= sec + 1;
                        if(sec == 60) begin
                            sec <= 0;
                        end
                    end
                end
                default: begin
                    //do nothing
                end
            endcase
            if(cnt == 24999999) begin //闪烁控制
                flag <= ~flag;
            end
        end
        default: begin
            flag <= 0;
        end
    endcase
end

endmodule

这里使用状态机实现按键控制，通过按键的不同组合控制秒表的启动、停止、复位和调整。同时，使用标志位来控制数码管的闪烁，以提示用户处于调整状态。