esp32 iic如何读取寄存器
时间: 2023-07-18 09:42:30 浏览: 84
在ESP32中,我们可以使用`i2c_cmd_handle_t`类型的变量来操作I2C总线。要读取I2C设备的寄存器,我们需要执行以下步骤:
1. 初始化I2C总线
```c
i2c_config_t conf;
conf.mode = I2C_MODE_MASTER;
conf.sda_io_num = I2C_SDA_PIN;
conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
conf.scl_io_num = I2C_SCL_PIN;
conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
conf.master.clk_speed = I2C_FREQ_HZ;
i2c_param_config(I2C_NUM_0, &conf);
i2c_driver_install(I2C_NUM_0, conf.mode, I2C_RX_BUF_DISABLE, I2C_TX_BUF_DISABLE, 0);
```
2. 创建一个I2C命令句柄
```c
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
```
3. 添加要读取的寄存器地址
```c
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (device_address << 1) | I2C_MASTER_WRITE, true);
i2c_master_write_byte(cmd, register_address, true);
```
其中,`device_address`是I2C设备的地址,`register_address`是要读取的寄存器地址。
4. 读取寄存器数据
```c
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (device_address << 1) | I2C_MASTER_READ, true);
i2c_master_read_byte(cmd, &data, I2C_MASTER_ACK);
```
其中,`data`是读取到的寄存器数据。
5. 结束I2C传输并释放命令句柄
```c
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000 / portTICK_RATE_MS);
i2c_cmd_link_delete(cmd);
```
以上是基于ESP32的I2C通讯读取寄存器的简单示例。需要注意的是,具体的实现方式可能会因I2C设备的不同而有所差异,请根据具体的设备文档进行实现。