I2C应用编程

目录

  1. 1. 1. 关键结构体
    1. 1.1. 1.1 struct i2c_msg
    2. 1.2. 1.2 struct i2c_rdwr_ioctl_data
  2. 2. 2. I2C 应用编程概述
    1. 2.1. 2.1 打开 I2C 设备
    2. 2.2. 2.2 设置从设备地址
    3. 2.3. 2.3 读写 I2C 数据
      1. 2.3.1. 2.3.1 写入数据
      2. 2.3.2. 2.3.2 读取数据
    4. 2.4. 2.4 使用 ioctl 进行复杂读写操作
      1. 2.4.1. 2.4.1 写入多个字节
      2. 2.4.2. 2.4.2 读取寄存器数据
  3. 3. 3. 常用的 ioctl 命令
  4. 4. 4. 完整的 I2C 应用层示例
  5. 5. 5. 使用 i2c-tools 进行调试
    1. 5.1. 5.1 i2cdetect
    2. 5.2. 5.2 i2cget
    3. 5.3. 5.3 i2cset
    4. 5.4. 5.4 i2cdump
  6. 6. 6. 总结

I2C<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“>（Inter-Integrated Circuit<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>）是一种广泛用于嵌入式系统的串行通信协议<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，允许多个设备通过两根数据线进行通信<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。在 Linux 系统中<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，I2C 设备通常挂载在 /dev 目录下<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，使用如 /dev/i2c-X 这样的设备文件进行访问<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。通过系统调用和特定的 I2C 操作命令<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，应用层程序可以与 I2C 设备进行读写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

本教程将介绍如何使用 Linux 提供的 I2C 接口进行编程<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，详细讲解关键的结构体<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、系统调用以及常用的 I2C 工具<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，以帮助开发者更好地理解和操作 I2C 设备<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

1. 关键结构体

1.1 struct i2c_msg

i2c_msg 是 I2C 消息的描述结构体<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，用于定义一次 I2C 通信中的单个传输消息<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。它可以是读或写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，并包含目标设备的地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、数据缓冲区和数据长度<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_msg {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    __u16 addr;    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 从设备的地址
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    __u16 flags;   "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 操作标志位
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    __u16 len;     "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 要发送/接收的数据长度
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    __u8 *buf;     "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 数据缓冲区指针
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">};

主要标志位<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

  • I2C_M_RD: 表示读操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。如果未设置此标志<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，则表示写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。
  • I2C_M_TEN: 表示使用 10 位地址模式<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。
  • I2C_M_STOP: 表示在消息结束时生成 STOP 信号<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

1.2 struct i2c_rdwr_ioctl_data

i2c_rdwr_ioctl_data 结构体用于通过 ioctl 系统调用执行 I2C 读写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。它包含一个 i2c_msg 数组和消息的数量<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_rdwr_ioctl_data {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_msg *"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">msgs;  "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 指向消息数组
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    __u32 nmsgs;           "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 消息的数量
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">};

2. I2C 应用编程概述

在用户空间中<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，I2C 编程的核心操作是<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

  1. 打开 I2C 设备<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：通过 open() 函数打开 /dev/i2c-X 设备文件<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。
  2. 设置从设备地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：使用 ioctl() 系统调用设置目标从设备的地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。
  3. 数据读写<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：通过 read() 和 write() 进行简单的读写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，或使用 ioctl() 进行复杂的多字节传输<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

2.1 打开 I2C 设备

使用 open() 函数打开 I2C 设备文件<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，例如 /dev/i2c-1<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">int file;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">file = open("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"/dev/i2c-1", O_RDWR);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (file < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to open the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"built_in"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">exit("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

2.2 设置从设备地址

通过 ioctl() 设置与哪个从设备进行通信<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">int addr = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x50; "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 从设备地址
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (ioctl(file, I2C_SLAVE, addr) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to acquire bus access and/or talk to slave");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"built_in"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">exit("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

I2C_SLAVE 是常用的 ioctl 命令<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，用于设置 I2C 从设备地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

2.3 读写 I2C 数据

2.3.1 写入数据

使用 write() 函数将数据写入 I2C 设备<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char buffer["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1] = { "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0xA0 };
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (write(file, buffer, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1) != "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to write to the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

2.3.2 读取数据

使用 read() 函数从 I2C 设备读取数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char buffer["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (read(file, buffer, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1) != "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to read from the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">} "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">else {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"built_in"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">printf("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Data read: 0x%02x\n", buffer["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0]);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

2.4 使用 ioctl 进行复杂读写操作

对于更复杂的读写操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“>（如多字节传输<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>）<h-char class=“bd bd-beg“>，可以使用 I2C_RDWR 命令结合 i2c_rdwr_ioctl_data 来实现<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

2.4.1 写入多个字节

假设要向寄存器 0x10 写入两个字节的数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char outbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">3] = { "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x10, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x01, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x02 };
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_msg "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages[1];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].addr  = addr;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].flags = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0;  "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 写操作
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].len   = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">3;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].buf   = outbuf;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_rdwr_ioctl_data "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data.msgs  = messages;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data.nmsgs = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (ioctl(file, I2C_RDWR, &ioctl_data) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to write to the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

2.4.2 读取寄存器数据

通常<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，读取寄存器数据需要先写入寄存器地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，再读取其数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。例如<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，读取寄存器 0x10<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char reg = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x10;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char inbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_msg "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages[2];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].addr  = addr;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].flags = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0;  "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 写操作
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].len   = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].buf   = &reg;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].addr  = addr;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].flags = I2C_M_RD;  "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 读操作
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].len   = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].buf   = inbuf;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_rdwr_ioctl_data "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data.msgs  = messages;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data.nmsgs = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">2;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (ioctl(file, I2C_RDWR, &ioctl_data) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to read from the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">} "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">else {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"built_in"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">printf("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Register 0x10 read: 0x%02x\n", inbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0]);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

3. 常用的 ioctl 命令

  • I2C_SLAVE: 设置从设备地址<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。
  • I2C_RDWR: 执行多条 I2C 消息<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“>（读或写<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>）<h-char class=“bd bd-beg“>，对应 i2c_rdwr_ioctl_data<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

4. 完整的 I2C 应用层示例

以下是一个完整的示例程序<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，展示如何通过 I2C 接口读取和写入数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>：

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight c"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"meta"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">#"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">include "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"><stdio.h>
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"meta"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">#"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">include "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"><fcntl.h>
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"meta"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">#"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">include "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"><sys/ioctl.h>
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"meta"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">#"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">include "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"><linux/i2c-dev.h>
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"meta"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">#"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">include "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"><unistd.h>
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">int "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title function_"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">main"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"params"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">() {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">int file;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">int addr = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x50; "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// I2C 从设备地址
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 打开 I2C 设备
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if ((file = open("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"/dev/i2c-1", O_RDWR)) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to open the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">return "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    }
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 设置从设备地址
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (ioctl(file, I2C_SLAVE, addr) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to acquire bus access and/or talk to slave");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">return "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    }
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 写入数据到寄存器 0x10
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char outbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">3] = { "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x10, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x01, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x02 };
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (write(file, outbuf, "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">3) != "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">3) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to write to the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">return "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    }
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"comment"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">// 读取寄存器 0x10 的值
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char reg = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0x10;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">unsigned "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"type"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">char inbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_msg "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">messages[2];
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].addr  = addr;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].flags = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].len   = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0].buf   = &reg;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].addr  = addr;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].flags = I2C_M_RD;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].len   = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    messages["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1].buf   = inbuf;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"class"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">struct "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2c_rdwr_ioctl_data "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"title"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">ioctl_data;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    ioctl_data.msgs  = messages;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    ioctl_data.nmsgs = "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">2;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">if (ioctl(file, I2C_RDWR, &ioctl_data) < "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0) {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        perror("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Failed to read from the i2c bus");
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">return "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">1;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    } "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">else {
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">        "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"built_in"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">printf("bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"string"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">"Register 0x10 read: 0x%02x\n", inbuf["bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0]);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    }
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    close(file);
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">    "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"keyword"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">return "bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"number"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">0;
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">}

5. 使用 i2c-tools 进行调试

i2c-tools 是一组用于调试 I2C 设备的工具集<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，其中包括 i2cdetect<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、i2cget<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、i2cset 和 i2cdump 等常用工具<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。以下是这些工具的使用介绍<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

5.1 i2cdetect

i2cdetect 用于扫描 I2C 总线<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，查看哪些设备在响应<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight bash"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2cdetect -y 1

5.2 i2cget

i2cget 用于读取 I2C 设备寄存器的数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight bash"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2cget -y 1 0x50 0x00

5.3 i2cset

i2cset 用于向 I2C 设备写入数据<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight bash"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2cset -y 1 0x50 0x00 0xFF

5.4 i2cdump

i2cdump 用于读取 I2C 设备的所有寄存器<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，并以十六进制输出<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"highlight bash"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"code"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">
"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">"line"bd bd-beg">"bd-box"bd bd-beg">">"bd bd-beg">">i2cdump -y 1 0x50

6. 总结

I2C 是嵌入式系统中常见的通信协议<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，在 Linux 中提供了丰富的用户空间接口来与设备交互<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。通过使用 open()<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、read()<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>、write() 和 ioctl() 等系统调用<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，开发者可以轻松对 I2C 设备进行操作<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。此外<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，i2c-tools 提供了一组命令行工具<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，能够帮助开发者快速调试和测试 I2C 总线设备<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。在嵌入式开发和硬件调试中<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，这些工具和接口都是非常重要的<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。

如需进一步了解 i2c-tools 的源码和开发方法<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>，你可以访问 i2c-tools 官方源码仓库<span class=<h-char class=“bd bd-beg“>“bd-box<h-char class=“bd bd-beg“>“><h-char class=“bd bd-beg“>。