SHT20 是一款高精度的温湿度传感器，常用于环境监测和自动化控制系统中。以下是 SHT20 温湿度传感器的 C 语言驱动示例，展示了如何通过 I2C 通信与 SHT20 传感器进行通信以获取温度和湿度数据。
驱动流程
- 初始化 I2C 通信
- 发送命令读取温度或湿度数据
- 解析传感器返回的原始数据
- 将原始数据转换为实际温度和湿度值
主要命令
- 测量湿度命令: 0xE5
- 测量温度命令: 0xE3
- 设备地址: 0x40 (7位地址)
示例代码
#include <stdio.h>
#include <stdint.h>
#include <unistd.h> // for usleep
#include <math.h> // for conversion functions
#include <i2c/smbus.h> // I2C communication
#include <fcntl.h> // for file control
#include <linux/i2c-dev.h> // for I2C operations
#include <sys/ioctl.h> // for I2C device control#define SHT20_I2C_ADDR 0x40 // SHT20 I2C address
#define TEMP_MEASURE_NO_HOLD 0xF3 // Measure temperature, no hold master mode
#define HUMI_MEASURE_NO_HOLD 0xF5 // Measure humidity, no hold master mode// Function to read raw data from the sensor
int SHT20_ReadRawData(int file, uint8_t command, uint16_t *data) {// Write the command to the sensorif (write(file, &command, 1) != 1) {perror("Failed to write command to the sensor");return -1;}// Delay to allow measurement (85ms)usleep(85000);// Read 2 bytes of data and 1 checksum byteuint8_t buffer[3];if (read(file, buffer, 3) != 3) {perror("Failed to read data from the sensor");return -1;}// Combine the two bytes into a single 16-bit value*data = (buffer[0] << 8) | buffer[1];return 0;
}// Function to initialize I2C communication
int I2C_Init(const char *device, uint8_t addr) {int file = open(device, O_RDWR);if (file < 0) {perror("Failed to open I2C bus");return -1;}if (ioctl(file, I2C_SLAVE, addr) < 0) {perror("Failed to set I2C address");close(file);return -1;}return file;
}// Function to calculate temperature from raw data
float SHT20_CalculateTemperature(uint16_t raw_temp) {raw_temp &= ~0x0003; // Clear the status bitsreturn -46.85 + 175.72 * (raw_temp / 65536.0);
}// Function to calculate humidity from raw data
float SHT20_CalculateHumidity(uint16_t raw_humi) {raw_humi &= ~0x0003; // Clear the status bitsreturn -6.0 + 125.0 * (raw_humi / 65536.0);
}int main() {const char *i2c_device = "/dev/i2c-1"; // I2C device on Raspberry Piint file = I2C_Init(i2c_device, SHT20_I2C_ADDR);if (file < 0) {return -1;}uint16_t raw_temp, raw_humi;// Read temperatureif (SHT20_ReadRawData(file, TEMP_MEASURE_NO_HOLD, &raw_temp) == 0) {float temperature = SHT20_CalculateTemperature(raw_temp);printf("Temperature: %.2f C\n", temperature);}// Read humidityif (SHT20_ReadRawData(file, HUMI_MEASURE_NO_HOLD, &raw_humi) == 0) {float humidity = SHT20_CalculateHumidity(raw_humi);printf("Humidity: %.2f %%\n", humidity);}close(file);return 0;
}
代码说明
- I2C 初始化:
I2C_Init()函数用于打开 I2C 设备并设置 SHT20 的从机地址。 - 读取原始数据:
SHT20_ReadRawData()函数发送测量命令，并从传感器读取 16 位的原始数据。 - 温湿度计算:
SHT20_CalculateTemperature()和SHT20_CalculateHumidity()函数用于将原始数据转换为实际的温度和湿度值。 - 结果输出: 程序最终输出测量的温度和湿度。
依赖库
你需要在系统上安装 I2C 库和头文件。可以通过以下命令安装：
sudo apt-get install libi2c-dev
注意事项
- I2C 通信的设备文件通常为
/dev/i2c-1，但具体情况可能因平台而异。 - 在运行代码之前，请确保已经正确连接 SHT20 传感器并启用了 I2C 通信。
结论
此 C 语言驱动通过 I2C 与 SHT20 温湿度传感器通信，读取温度和湿度并将其转换为实际值。