STM32 Peripheral driver--dht11 temperature and humidity sensor

Tests have been performed on the STM32. This example uses the PC0 pin to connect the DHT11 data pin.

In the main function, call the Dth11_test function in the code below.

Data definition:     //----The following variables are global variables--------    //----High temperature 8-bit = = u8t_data_h------    //----Temperature Low 8-bit = = u8t_data_l------    //----Humidity 8-bit = = u8rh_data_h-----    //---- Low humidity 8-bit = = u8rh_data_l-----    //----Check 8-bit = = U8checkdata-----u8  u8t_data_h,u8t_data_l,u8rh_data_h
, U8rh_data_l,u8checkdata;

u8  u8t_data_h_temp,u8t_data_l_temp,u8rh_data_h_temp,u8rh_data_l_temp,u8checkdata_temp; #define BOOL unsigned char #ifndef true #define TRUE 1 #endif #ifndef false #define FALSE 0 #endif static void Dht11_da Tapin_configure_output (void) {     GPIO_InitTypeDef  gpio_initstructure;   
      //rcc_apb2periphclockcmd (Rcc_apb2periph_afio, DISABLE);     rcc_apb2periphclockcmd (RCC_APB2PERIPH_GPIOC, enable);    /enable PC Port clock                       gpio_initstrucTure. Gpio_pin = gpio_pin_0;                //pc.0 port configuration  & nbsp;   gpio_initstructure.gpio_mode = gpio_mode_out_pp;         //push-pull output      gpio_initstructure.gpio_speed = Gpio_speed_
50MHz;
     gpio_init (GPIOC, &gpio_initstructure); } static void Dht11_datapin_configure_input (void) {       GPIO_InitTypeDef  datapin;& nbsp;              datapin.gpio_pin = gpio_pin_0;                       datapin.gpio_mode = Gpio_mode_in_ floating;         //hover           datapin.gpio_speed = Gpio_
Speed_50mhz;
    gpio_init (GPIOC, &datapin); } BOOL dht11_get_databit (void) {    uint8_t val;           val = Gpio_readinputdatabit (GPIOC, gpio_pin_0);     if (val = = bit_reset) {        return FALSE;     }else{&
nbsp;       return TRUE;    &nbsp}} void Dht11_set_databit (BOOL level) {    if (level = = TRUE) {    &nbs
p;   gpio_setbits (GPIOC, gpio_pin_0);     }else{        gpio_resetbits (GPIOC, gpio_pin_0);    &NBSP}} void Mdelay (u16 ms)   {    if (ms! = 0) {        delay_ms (ms)
;    &nbsp}} void Udelay (u16 us)   {    if (us! = 0) {       &nbsp
;d Elay_us (US);     }} static uint8_t dht11_read_byte (void) {          uint8_t i; &nbs
P     uint8_t data = 0;            &NBsp;                    for (i = 0; i < 8; i+ +)             {             data & lt;<= 1;                    while (!
Dht11_get_databit ()));
        udelay (10);
        udelay (10);

        udelay (10);         if (Dht11_get_databit ())     {      
     data |= 0x1;
            while (Dht11_get_databit ());        &nbsp, else{                & 

nbsp;}                                    return data; }   static uint8_t dht11_start_sampling (void) {    dht11_datapin_configure_output ();   
  //Host pull down 18ms        dht11_set_databit (FALSE);
    mdelay (18);
    dht11_set_databit (TRUE);
    //bus pulled by pull-up resistor high host delay 20US     Udelay (10);
    udelay (10);
    udelay (10);
    udelay (10);

    //host set as input to determine the slave response signal     dht11_set_databit (TRUE);

    dht11_datapin_configure_input ();     //Determine if the slave has a low-level response signal to jump out if it does not respond, and the response runs down            if (! Dht11_get_databit ())         //t!           { & nbsp  //Determine if the slave is emitting a 80us low-level response signal whether it ends             while ((!
Dht11_get_databit ()));     //printf ("DHT11 answers.\r\n");
    //determine if the slave emits a high level of 80US, and then enters the data receiving State        while ((Dht11_get_databit ()));
       return 1;     }     return 0;                void Dht11_get_data (void) {          U8 temp;     if (dht11_st Art_sampling ()) {       //printf ("DHT11 is ready to transmit data\r\n");         //Data Reception status               
   u8rh_data_h_temp = Dht11_read_byte ();
        u8rh_data_l_temp = Dht11_read_byte ();
        u8t_data_h_temp     = dht11_read_byte ();
        u8t_data_l_temp     = dht11_read_byte ();        u8checkdata_temp = Dht11_read_byte ();        /* Data transmission finishes, pull the bus high */    & nbsp;   dht11_datapin_configure_output ();            dht11_
Set_databit (TRUE);        //data validation         temp= (u8t_data_h_
TEMP+U8T_DATA_L_TEMP+U8RH_DATA_H_TEMP+U8RH_DATA_L_TEMP);         if (temp==u8checkdata_temp)         { 
           u8rh_data_h=u8rh_data_h_temp;
            u8rh_data_l=u8rh_data_l_temp;
            u8t_data_h=u8t_data_h_temp;
            u8t_data_l=u8t_data_l_temp;             u8checkdata=u8checkdata_temp;             printf ("DHT11 tempature%d.%d  humidity%d. %d \ r \ n ",                 u8t_data_h,                  u8t_data_l,                  U8rh_data_h,    

             u8t_data_l);       }else{            printf ("checksum
Failure \ r \ n ");       }     }else{        printf ("DHT11 Didn ' t answer. Sampling failed.
\ r \ n ");    &nbsp}} void Dth11_test () {    while (1)    &nbsp {        dht11_get_data ()         delay_ms (1000);




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