FPGA代码，IIC读写24LC04B

下面是一个简单的FPGA代码，用于通过IIC总线读写24LC04B芯片：

module IIC_24LC04B(
    input wire clk,
    input wire reset,
    input wire start,
    input wire stop,
    input wire [7:0] addr,
    input wire [7:0] data_in,
    output reg [7:0] data_out,
    output reg ack
);

reg [7:0] state;
reg [7:0] count;
reg [7:0] reg_addr;
reg [7:0] reg_data;
reg sda;
reg scl;
wire sda_i;
wire sda_oen;
wire sda_en;
wire scl_en;

assign sda_en = (state == 1 || state == 3 || state == 5 || state == 7 || state == 9);
assign scl_en = (state == 2 || state == 4 || state == 6 || state == 8 || state == 10);

// IIC总线状态定义
localparam IDLE = 0;
localparam START = 1;
localparam ADDR = 2;
localparam ADDR_ACK = 3;
localparam DATA_IN = 4;
localparam DATA_IN_ACK = 5;
localparam DATA_OUT = 6;
localparam DATA_OUT_ACK = 7;
localparam STOP = 8;

always @(posedge clk) begin
    if (reset) begin
        state <= IDLE;
        count <= 0;
        sda <= 1;
        scl <= 1;
        reg_addr <= 0;
        reg_data <= 0;
        ack <= 0;
    end else begin
        case (state)
            IDLE: begin
                if (start) begin
                    sda <= 0;
                    scl <= 0;
                    state <= START;
                end
            end
            START: begin
                sda <= 1;
                scl <= 1;
                state <= ADDR;
            end
            ADDR: begin
                sda <= addr[count];
                state <= ADDR_ACK;
            end
            ADDR_ACK: begin
                sda <= 1;
                state <= (ack == 0) ? DATA_IN : DATA_OUT;
            end
            DATA_IN: begin
                sda <= 1;
                state <= DATA_IN_ACK;
            end
            DATA_IN_ACK: begin
                sda <= 1;
                if (ack == 0) begin
                    state <= STOP;
                    data_out <= reg_data;
                end else begin
                    state <= DATA_OUT;
                end
            end
            DATA_OUT: begin
                sda <= (reg_data[count] == 1);
                state <= DATA_OUT_ACK;
            end
            DATA_OUT_ACK: begin
                sda <= 1;
                if (ack == 0) begin
                    state <= (count == 7) ? STOP : DATA_OUT;
                    count <= count + 1;
                end
            end
            STOP: begin
                sda <= 0;
                scl <= 0;
                state <= IDLE;
            end
        endcase
    end
end

// IIC总线信号同步
assign sda_i = sda;
assign sda_oen = (sda_en) ? 1 : 0;
SB_IO #(
    .PIN_TYPE(6'b 101001),
    .PULLUP(1'b 1),
    .NEG_TRIGGER(1'b 1),
    .IO_STANDARD("SB_LVCMOS")
) iic_sda (
    .PACKAGE_PIN(sda_i),
    .OUTPUT_ENABLE(sda_oen),
    .D_OUT_0(sda),
    .D_IN_0(sda)
);

SB_IO #(
    .PIN_TYPE(6'b 101001),
    .PULLUP(1'b 1),
    .NEG_TRIGGER(1'b 1),
    .IO_STANDARD("SB_LVCMOS")
) iic_scl (
    .PACKAGE_PIN(scl),
    .OUTPUT_ENABLE(scl_en),
    .D_OUT_0(scl),
    .D_IN_0(scl)
);

// 读写24LC04B芯片
always @(posedge clk) begin
    if (reset) begin
        ack <= 0;
        reg_addr <= 0;
        reg_data <= 0;
    end else if (start) begin
        reg_addr <= addr;
        count <= 0;
        reg_data <= data_in;
    end else if (state == DATA_OUT_ACK) begin
        if (count == 7) begin
            ack <= 1;
        end else begin
            reg_addr <= reg_addr + 1;
        end
        count <= count + 1;
        reg_data <= data_in;
    end else if (state == DATA_IN_ACK) begin
        ack <= 1;
    end
end

endmodule

使用方法：

1. 将代码保存为 IIC_24LC04B.v 文件。
2. 根据您的FPGA型号和开发板，修改 iic_sda 和 iic_scl 的属性。
3. 实例化 IIC_24LC04B 模块，并将 clk, reset, start, stop, addr, data_in, data_out 和 ack 连接到您的FPGA设计中。
4. 在您的FPGA设计中使用该模块实现对24LC04B芯片的读写操作。

注意事项：

1. 该代码只是一个参考，具体实现需要根据您的FPGA型号和开发板进行修改。
2. 在使用该代码时，请仔细阅读24LC04B芯片的数据手册，以确保正确使用IIC总线进行读写操作。