续写，忽视长度限制

好的，以下是续写的完整代码：

module top(
    input         clk,
    input         rst,
    output [3:0]  led,
    output [3:0]  sw
);

// BME280接口
input wire bme280_sck, bme280_cs;
output reg bme280_sda;

// Pmod RTCC接口
input wire rtcc_sck, rtcc_cs;
output reg rtcc_sda;

// Pmod OLED接口
input wire oled_sck, oled_dc, oled_cs;
output reg oled_sda;

// 辅助变量
reg [31:0] wait_count;
reg [2:0]  state;
reg [3:0]  led_value;

// 辅助函数
function void i2c_start(input wire sck, input wire cs, inout reg sda);
    sck = 1;
    cs = 0;
    sda = 0;
    sck = 0;
endfunction

function void i2c_stop(input wire sck, input wire cs, inout reg sda);
    sck = 0;
    sda = 0;
    sck = 1;
    cs = 1;
endfunction

function void i2c_write_bit(input wire sck, input wire cs, inout reg sda, input wire bit);
    sda = bit;
    sck = 1;
    sck = 0;
endfunction

function void i2c_write_byte(input wire sck, input wire cs, inout reg sda, input byte data);
    for (i = 0; i < 8; i = i + 1) begin
        i2c_write_bit(sck, cs, sda, data[i]);
    end
    i2c_write_bit(sck, cs, sda, 1); // 发送停止位
endfunction

function byte i2c_read_bit(input wire sck, input wire cs, inout reg sda, input wire ack);
    sck = 1;
    bit = sda;
    sck = 0;
    if (ack) begin
        sda = 0;
    end
    sck = 1;
    sck = 0;
    sda = bit;
    return bit;
endfunction

function byte i2c_read_byte(input wire sck, input wire cs, inout reg sda, input wire ack);
    byte data = 0;
    for (i = 0; i < 8; i = i + 1) begin
        data[i] = i2c_read_bit(sck, cs, sda, (i == 7) ? ack : 0);
    end
    return data;
endfunction

function void oled_init();
    oled_write_cmd(0xAE); // 关闭显示
    oled_write_cmd(0xD5); // 设置时钟分频因子
    oled_write_cmd(0x80); // 分频因子为1
    oled_write_cmd(0xA8); // 设置驱动路数
    oled_write_cmd(0x1F); // 使用外部VCC供电，32路COM行
    oled_write_cmd(0xD3); // 设置显示偏移
    oled_write_cmd(0x00);
    oled_write_cmd(0x40); // 设置显示起始行
    oled_write_cmd(0x8D); // 设置电荷泵
    oled_write_cmd(0x14); // 开启电荷泵