module ws2812_ctrl(
    input                   sys_clk     ,//系统时钟，50MHz
    input                   sys_rst_n   ,//系统复位，下降沿有效
    input                   bit         ,//data_cfg给的bit
    input        [3: 0]     opcode      ,
    input        [3: 0]     data        ,
    input        [1: 0]     dev_id      ,//设备地址

    output  reg  [4: 0]     bit_num     ,//bit计数寄存器
    output  reg  [6: 0]     led_num     ,//led计数寄存器
    output  reg  [1: 0]     frame       ,//帧
    output                  dout//点阵输出
);
parameter T0H = 4'd13,//0高电平时间
          T0L = 5'd30,//0低电平时间
          T1H = 5'd30,//1高电平时间
          T1L = 5'd30,//1低电平时间
          RST = 26'd5_000_000;//复位时间
parameter BIT = 5'd24,
          LED = 7'd64;
reg [5: 0] cnt_0;//0bit计数寄存器
wire       add_cnt_0;
wire       end_cnt_0;

reg [5: 0] cnt_1;//1bit计数寄存器
wire       add_cnt_1;
wire       end_cnt_1;

reg [25: 0] cnt_rst;//复位计数寄存器
wire        add_cnt_rst;
wire        end_cnt_rst;

//bit计数寄存器
wire        add_bit_num;
wire        end_bit_num;

//led计数寄存器
wire        add_led_num;
wire        end_led_num;

reg         rst_flag   ;//复位标志
reg         start_flag ;

//开始信号
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        start_flag <= 1'b0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        start_flag <= 1'b0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0010))begin
        start_flag <= 1'b1;
    end 
    else begin
        start_flag <= start_flag;
    end 
end 
//bit0计数器设计
always @(posedge sys_clk or negedge sys_rst_n) begin
    if(!sys_rst_n)begin
        cnt_0 <= 6'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        cnt_0 <= 6'd0;
    end 
    else if(add_cnt_0)begin
        if(end_cnt_0)begin
            cnt_0 <= 6'd0;
        end 
        else begin
            cnt_0 <= cnt_0 + 1'd1;
        end 
    end 
    else begin
        cnt_0 <= cnt_0;
    end 
end
assign add_cnt_0 = start_flag && ~bit && ~rst_flag;
assign end_cnt_0 = add_cnt_0 && cnt_0 == T0H + T0L - 1'd1;
//bit1计数器设计
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        cnt_1 <= 6'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        cnt_1 <= 6'd0;
    end 
    else if(add_cnt_1)begin
        if(end_cnt_1)begin
            cnt_1 <= 6'd0;
        end 
        else begin
            cnt_1 <= cnt_1 + 1'd1;
        end 
    end 
    else begin
        cnt_1 <= cnt_1;
    end 
end 
assign add_cnt_1 = start_flag && bit && ~rst_flag;
assign end_cnt_1 = add_cnt_1 && cnt_1 == T1H + T1L - 1'd1;
//bit计数器设计
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        bit_num <= 5'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        bit_num <= 5'd0;
    end 
    else if(add_bit_num)begin
        if(end_bit_num)begin
            bit_num <= 5'd0;
        end 
        else begin
            bit_num <= bit_num + 1'd1;
        end 
    end 
    else begin
        bit_num <= bit_num;
    end 
end 
assign add_bit_num = end_cnt_0 || end_cnt_1;//0bit或者1bit结束，bit计数器加1
assign end_bit_num = add_bit_num && bit_num == BIT - 1'd1;

//led计数器设计
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        led_num <= 7'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        led_num <= 7'd0;
    end 
    else if(add_led_num)begin
        if(end_led_num)begin
            led_num <= 7'd0;
        end 
        else begin
            led_num <= led_num + 1'd1;
        end 
    end 
    else begin
        led_num <= led_num;
    end 
end 
assign add_led_num = end_bit_num;
assign end_led_num = add_led_num && led_num == LED - 1'd1;

//rst_flag约束
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        rst_flag <= 1'b0;
    end 
    else if(end_led_num)begin
        rst_flag <= 1'b1;
    end 
    else if(end_cnt_rst)begin
        rst_flag <= 1'b0;
    end 
    else begin
        rst_flag <= rst_flag;
    end 
end 
//复位计数器设计
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        cnt_rst <= 26'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        cnt_rst <= 26'd0;
    end 
    else if(add_cnt_rst)begin
        if(end_cnt_rst)begin
            cnt_rst <= 26'd0;
        end 
        else begin
            cnt_rst <= cnt_rst + 1'd1;
        end 
    end 
    else begin
        cnt_rst <= cnt_rst;
    end 
end 
assign add_cnt_rst = rst_flag;
assign end_cnt_rst = add_cnt_rst && cnt_rst == RST - 1'd1;
//frame约束
always @(posedge sys_clk or negedge sys_rst_n)begin
    if(!sys_rst_n)begin
        frame <= 2'd0;
    end 
    else if((dev_id == 2'd3) && (opcode == 4'b0001))begin
        frame <= 2'd0;
    end 
    else if((frame == 2'd3) && (end_cnt_rst))begin
        frame <= 2'd0;
    end 
    else if(end_cnt_rst)begin
        frame <= frame + 1'd1;
    end 
    else begin
        frame <= frame;
    end 
end 
///////////////输出///////////////
assign dout = (rst_flag == 0) ? (((bit == 0 && cnt_0 < T0H) ? 1'b1 : 1'b0) | ((bit == 1 && cnt_1 < T1H) ? 1'b1 : 1'b0)): 1'b0;
endmodule