182 lines
4.6 KiB
C
182 lines
4.6 KiB
C
#include "sht40.h"
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#include "i2cs.h"
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#include "delay.h"
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#define SHT40_SDA_PORT I2C1_SDA_GPIO_Port
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#define SHT40_SDA_PIN I2C1_SDA_Pin
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#define SHT40_SCL_PORT I2C1_SCL_GPIO_Port
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#define SHT40_SCL_PIN I2C1_SCL_Pin
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#define SHT40_I2C_ADDRESS 0x44
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#define SHT40_MEASURE_CMD 0xFD // 2*8-bit T-data:8-bit CRC:2*8-bit RH-data: 8-bit CRC
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static i2c_t *_sht40_i2c;
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static TIM_TypeDef *_timer_us;
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static uint8_t crc8(uint8_t *data, uint8_t len);
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static void _delay_us(uint32_t us)
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{
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if (_timer_us != NULL)
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{
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delay_hardware_us(_timer_us, us);
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}
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else
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{
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delay_us(us);
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}
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}
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void sht40_test(void)
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{
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float32 temperature = 0;
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float32 humidity = 0;
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sht40_read(&temperature, &humidity);
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__NOP();
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}
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/**
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* @brief 初始化 SHT40 传感器
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*
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* 该函数用于初始化 SHT40 传感器，包括创建 I2C 通讯所需的 GPIO 引脚和 I2C 通讯对象。
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*
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* 初始化完成后，sht40_i2c 变量将用于后续的 SHT40 传感器通信。
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*/
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void sht40_init(TIM_TypeDef *timer_us)
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{
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DBG_ASSERT(timer_us != NULL __DBG_LINE);
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if (timer_us != NULL)
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{
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_timer_us = timer_us;
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ENABLE_TIM_COUNT(_timer_us);
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}
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i2c_gpio_group_t gpios;
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gpios.scl = gpio_create(SHT40_SCL_PORT, SHT40_SCL_PIN);
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gpios.sda = gpio_create(SHT40_SDA_PORT, SHT40_SDA_PIN);
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_sht40_i2c = i2c_create(gpios, 10);
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DBG_ASSERT(_sht40_i2c != NULL __DBG_LINE);
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// sht40_test(); // 测试 SHT40
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}
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/**
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* @brief 初始化 SHT40 传感器
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*
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* 此函数用于初始化 SHT40 温湿度传感器，以便进行后续的温度和湿度测量。
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*
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* 注意：该函数没有返回值，也不接受任何参数。
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*/
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void sht40_dinit(void)
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{
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GPIO_SET_ANALOG(SHT40_SDA_PORT, SHT40_SDA_PIN);
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GPIO_SET_ANALOG(SHT40_SCL_PORT, SHT40_SCL_PIN);
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}
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/**
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* @brief 读取温湿度传感器数据
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*
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* 从温湿度传感器读取温度和湿度数据，并将读取到的数据存储在传入的浮点数指针指向的位置。
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*
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* @param temperature 用于存储读取到的温度值的浮点数指针
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* @param humidity 用于存储读取到的湿度值的浮点数指针
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*/
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BOOL sht40_read(float32 *temperature, float32 *humidity)
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{
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uint8_t data[6];
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osel_memset(data, 0, ARRAY_LEN(data));
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// 发送开始信号
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_sht40_i2c->interface.start(_sht40_i2c);
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// 发送写入地址命令
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_sht40_i2c->interface.write_byte(_sht40_i2c, SHT40_I2C_ADDRESS << 1);
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// 等待写入地址命令响应
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if (_sht40_i2c->interface.wait_ack(_sht40_i2c) == FALSE)
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{
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return FALSE;
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}
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// 发送测量命令
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_sht40_i2c->interface.write_byte(_sht40_i2c, SHT40_MEASURE_CMD);
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// 等待测量命令响应
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if (_sht40_i2c->interface.wait_ack(_sht40_i2c) == FALSE)
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{
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return FALSE;
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}
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// 停止I2C总线
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_sht40_i2c->interface.stop(_sht40_i2c);
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_delay_us(10000); // 根据 SHT40 数据手册，等待至少 10ms
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// 发送开始信号
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_sht40_i2c->interface.start(_sht40_i2c);
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// 发送写入地址命令
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_sht40_i2c->interface.write_byte(_sht40_i2c, (SHT40_I2C_ADDRESS << 1) | 1);
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// 等待写入地址命令响应
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if (_sht40_i2c->interface.wait_ack(_sht40_i2c) == FALSE)
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{
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return FALSE;
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}
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for (uint8_t i = 0; i < ARRAY_LEN(data); i++)
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{
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if (i == 5)
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{
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data[i] = _sht40_i2c->interface.read_byte(_sht40_i2c, FALSE);
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}
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else
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{
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data[i] = _sht40_i2c->interface.read_byte(_sht40_i2c, TRUE);
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}
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}
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// 停止I2C总线
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_sht40_i2c->interface.stop(_sht40_i2c);
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*temperature = 0;
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*humidity = 0;
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if (crc8(&data[0], 2) != data[2] || crc8(&data[3], 2) != data[5])
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{
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return FALSE;
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}
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else
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{
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*temperature = (float32)((uint16_t)data[0] << 8 | data[1]) * 175 / 65535 - 45;
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*humidity = (float32)((uint16_t)data[3] << 8 | data[4]) * 125 / 65535 - 6;
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if (*humidity > 100)
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{
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*humidity = 100;
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}
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if (*humidity < 0)
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{
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*humidity = 0;
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}
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return TRUE;
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}
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}
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/**
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* @brief crc8校验函数，多项式为 x^8 + x^5 + x^4 + 1
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* @param data 要校验的数据
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* @param len 要校验的数据的字节数
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* @retval 校验结果
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* @note 该校验适合SHT3温湿度传感器的数据校验
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*/
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static uint8_t crc8(uint8_t *data, uint8_t len)
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{
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const uint8_t polynomial = 0x31;
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uint8_t crc = 0xFF;
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int i, j;
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for (i = 0; i < len; ++i)
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{
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crc ^= *data++;
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for (j = 0; j < 8; ++j)
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{
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crc = (crc & 0x80) ? (crc << 1) ^ polynomial : (crc << 1);
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}
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}
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return crc;
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}
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