DHT11温湿度传感器

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DHT11是一款数字温湿度传感器，有效测量范围是温度0~50℃，湿度20~95%，DHT11是单总线通信设备，有自己的单总线通信协议(单线双向协议)，一次通讯时间4ms左右。

    在设计DHT11驱动程序时，需要提供两个API：初始化、读取温湿度数据！

    我们使用的主控芯片是TI的CC2530，主要是考虑到程序可以用在ZigBee中开发温湿度传感器设备，驱动程序在编写时，必须充分考虑编程规范，从而达到高可维护性、可读性的特点。

程序头文件：

/*******************************************************************
 * @file    hal_dht11.h
 * @brief   Temperature & Humidity Sensor Driver - DHT11
 *
 * Copyright (c) 2017~2020 ShenZhen IoT-College Technology Co., Ltd.
 * All rights reserved.
 *
 * @version 1.0.0
 * @author  IoT-College <[email protected]>
 * @date    2017-12-11 13:18:22
 *
 * @note        1. The official flagship store:
 *              Unopened
 *
 *              2. Blog:
 *              *GitHub: https://github.com/IoT-College
 *              *CSDN:   https://blog.csdn.net/IoT_College
 *              *StackOverflow:
 *              https://stackoverflow.com/users/9555987/iot-college
 *
 *              3. QQ Communication group:
 *              *Group 1: 575036716
 *              *Group 2: 684572410
 *              *Group 3: 587518203
 *******************************************************************/
#ifndef HAL_DHT11_H
#define HAL_DHT11_H

#ifdef __cplusplus
extern "C" {
#endif

/*******************************************************************
 *                          Includes
 *******************************************************************
 */
#include "hal_delay.h"


/*******************************************************************
 *               Constant-Macros And Enumerations
 *******************************************************************
 */

/** @brief   DHT11 GPIO
 */
#define HAL_DHT11_PORT          0
#define HAL_DHT11_PIN           6

/** @brief   DHT11 Data
 *      Temperature,
 *      Humidity
 */
typedef struct
{
    uint8 temp;
    uint8 humi;

    bool ok;
}halDHT11Data_t;


/*******************************************************************
 *                              API
 *******************************************************************
 */

/**
 * @fn          halDHT11Init
 *
 * @brief       Init. DHT11
 */
void halDHT11Init(void);

/**
 * @fn          halDHT11GetData
 *
 * @brief       Get data from DHT11
 *
 * @param       None
 *
 * @note        Temperature: 0~50 C
 *              Humidity: 20~95%
 */
halDHT11Data_t  halDHT11GetData(void);


#ifdef __cplusplus
}
#endif

#endif /* #ifndef HAL_DHT11_H */

  程序源文件：

/*******************************************************************
 * @file    hal_dht11.c
 * @brief   Temperature & Humidity Sensor Driver - DHT11
 *
 * Copyright (c) 2017~2020 ShenZhen IoT-College Technology Co., Ltd.
 * All rights reserved.
 *
 * @version 1.0.0
 * @author  IoT-College <[email protected]>
 * @date    2017-12-11 13:18:22
 *
 * @note        1. The official flagship store:
 *              UNopened
 *
 *              2. Blog:
 *              *GitHub: https://github.com/IoT-College
 *              *CSDN:   https://blog.csdn.net/IoT_College
 *              *StackOverflow:
 *              https://stackoverflow.com/users/9555987/iot-college
 *
 *              3. QQ Communication group:
 *              *Group 1: 575036716
 *              *Group 2: 684572410
 *              *Group 3: 587518203
 *******************************************************************/

/*******************************************************************
 *                          Includes
 *******************************************************************
 */
#include "hal_dht11.h"
#include "CC2530_IoConfig.h"


/*******************************************************************
 *               Constant-Macros And Enumerations
 *******************************************************************
 */

/** @brief   DHT11 Boolean
 */
#define HAL_DHT11_FALSE         0
#define HAL_DHT11_TRUE          1

/** @brief   DHT11 Status Code
 */
#define HAL_DHT11_SC_ERR                HAL_DHT11_FALSE
#define HAL_DHT11_SC_OK                 HAL_DHT11_TRUE
#define HAL_DHT11_SC_HUMI_OUTOFRANGE    0xF1
#define HAL_DHT11_SC_TEMP_OUTOFRANGE    0xF2
#define HAL_DHT11_SC_HT_OUTOFRANGE      0xF3

/** @brief   Delay Function
 *      us,
 *      ms
 */
#define HAL_DHT11_DELAY_US(x)   delayUsIn32Mhz((x))
#define HAL_DHT11_DELAY_MS(x)   delayMs(HAL_DELAY_32MHZ ,(x))

/** @brief   Set DHT11 GPIO
 *      output,
 *      input
 */
#define HAL_DHT11_IO_OUTPUT()   CC2530_GPIOMODE_CONFIG(HAL_DHT11_PORT,  \
                                                       HAL_DHT11_PIN,   \
                                                       CC2530_GPIO_OUTPUT)
#define HAL_DHT11_IO_INPUT()    CC2530_GPIOMODE_CONFIG(HAL_DHT11_PORT,  \
                                                       HAL_DHT11_PIN,   \
                                                       CC2530_GPIO_INPUT_PULLDOWN)
/** @brief   Set DHT11 GPIO Level
 *      low-level,
 *      high-level
 */
// set IO level
#define HAL_DHT11_IO_SET(port, pin, level){ \
  if(level) CC2530_GPIO_SET(port, pin);     \
  else CC2530_GPIO_CLEAR(port, pin);        \
}
// Set IO as high-level
#define HAL_DHT11_IO_SET_LO()  HAL_DHT11_IO_SET(HAL_DHT11_PORT, HAL_DHT11_PIN, 0)
// Set IO as low-level
#define HAL_DHT11_IO_SET_HI()  HAL_DHT11_IO_SET(HAL_DHT11_PORT, HAL_DHT11_PIN, 1)

/** @brief   DHT11 GPIO Status
 */
#define HAL_DHT11_IO_GET_STA(port, pin) CC2530_GPIO_GET(port, pin)
#define HAL_DHT11_IO()  HAL_DHT11_IO_GET_STA(HAL_DHT11_PORT, HAL_DHT11_PIN)

/** @brief   DHT11 Measurement range detection
 *      Temperature: 0~50 C
 *      Humidity: 20~95%RH
 */
#define HAL_DHT11_TEMP_OK(t)    ((t) <= 50)
#define HAL_DHT11_HUMI_OK(h)    ((h) >= 20 && (h) <= 95)


/*******************************************************************
 *                 Local Functions Declarations
 *******************************************************************
 */
static void halDHT11SetIdle(void);
static uint8 halDHT11ReadByte(void);
static uint8 halDHT11CheckData(uint8 TempI, uint8 HumiI);


/*******************************************************************
 *                          Global Functions
 *******************************************************************
 */

/**
 * @fn          halDHT11Init
 *
 * @brief   Init. DHT11
 */
void halDHT11Init(void)
{
    halDHT11SetIdle();
}

/**
 * @fn          halDHT11GetData
 *
 * @brief   Get data from DHT11
 *
 * @param   None
 *
 * @note        Temperature: 0~50 C
 *              Humidity: 20~95%
 */
halDHT11Data_t  halDHT11GetData(void)
{
    halDHT11Data_t dht11Dat = { .ok = 0 };
    uint8 HumiI, HumiF, TempI, TempF, CheckSum;

    /* >18ms, keeping gpio low-level */
    HAL_DHT11_IO_SET_LO();
    HAL_DHT11_DELAY_MS(60);

    HAL_DHT11_IO_SET_HI();

    /* Wait 20~40us then read ACK */
    HAL_DHT11_DELAY_US(35);
    HAL_DHT11_IO_INPUT();
    if(!HAL_DHT11_IO())
    {
        uint16 cnt = 1070; // ~1ms

        /* Wait for the end of ACK */
        while(!HAL_DHT11_IO() && cnt--);
        if(!cnt)
        {
            goto Exit;
        }

        /* ~80us, DHT11 GPIO will be set after ACK */
        cnt = 1070;  // ~1ms
        HAL_DHT11_DELAY_US(80);
        while(HAL_DHT11_IO() && cnt--);
        if(!cnt)
        {
            goto Exit;
        }

        /* Read data */
        HumiI = halDHT11ReadByte();
        HumiF = halDHT11ReadByte();
        TempI = halDHT11ReadByte();
        TempF = halDHT11ReadByte();
        CheckSum = halDHT11ReadByte();

        /* Checksum */
        if(CheckSum == (HumiI + HumiF + TempI + TempF))
        {
            dht11Dat.temp = TempI;
            dht11Dat.humi = HumiI;

            dht11Dat.ok = halDHT11CheckData(TempI, HumiI);
        }
    }

Exit:
    /* Idle */
    halDHT11SetIdle();

    return dht11Dat;
}


/*******************************************************************
 *                       Local Functions
 *******************************************************************
 */

/**
 * @fn          halDHT11SetIdle
 *
 * @brief       DHT11 Idle
 */
static void halDHT11SetIdle(void)
{
    HAL_DHT11_IO_OUTPUT();
    HAL_DHT11_IO_SET_HI();
}

/**
 * @fn          halDHT11ReadByte
 *
 * @brief       Read a byte from DHT11
 */
 static uint8 halDHT11ReadByte(void)
 {
    uint8 dat = 0;

    for(uint8 i = 0; i < 8; i++)
    {
        uint16 cnt = 5350;  // ~5ms

        /* Busy */
        while(!HAL_DHT11_IO() && cnt--);
        if(!cnt)
        {
            break;
        }

        /* Read bit based on high-level duration:
         *      26~28us: 0
         *      >70us:   1
         */
        HAL_DHT11_DELAY_US(50);
        if(HAL_DHT11_IO())
        {
            dat <<= 1;
            dat |= 1;
        }
        else
        {
            dat <<= 1;
            continue;
        }

        /* Waiting end */
        cnt = 1070;   // ~1ms
        while(HAL_DHT11_IO() && cnt--);
        if(!cnt)
        {
            break;
        }
    }

    return dat;
}

/**
 * @fn          halDHT11CheckData
 *
 * @brief       Check measured value
 */
static uint8 halDHT11CheckData(uint8 TempI, uint8 HumiI)
{
    if(HAL_DHT11_HUMI_OK(HumiI))
    {
      if(HAL_DHT11_TEMP_OK(TempI))
        return HAL_DHT11_SC_OK;
      else
        return HAL_DHT11_SC_TEMP_OUTOFRANGE;
    }

    if(HAL_DHT11_TEMP_OK(TempI))
      return HAL_DHT11_SC_HUMI_OUTOFRANGE;
    else
      return HAL_DHT11_SC_HT_OUTOFRANGE;
}