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root@hp:~# cat dht11.c
/*
DHT11 Library 0x01
copyright (c) Davide Gironi, 2011
Released under GPLv3.
Please refer to LICENSE file for licensing information.
*/
#include <stdio.h>
#include <string.h>
#include <sys/io.h>
#include <unistd.h>

#define PORT    0x37a           // Status Port
#define PIN     0               // Strobe - INWERTER !!!!
#define DHT11_Hi outb( inb(PORT) & ~(1<<PIN), PORT)
#define DHT11_Lo outb( inb(PORT) | 1<<PIN, PORT)
#define DHT11_INP (~inb(PORT) & 1<<PIN)

#define DHT11_ERROR 255

int temperature, humidity;

unsigned dht11_getdata(void)
{
    unsigned bits[5];
    unsigned i,j = 0;

    //reset port
    DHT11_Hi;   //high
    usleep(100000);

    //send request
    DHT11_Lo;   // low
    usleep(18000);
    printf("\nCheckpoint #0, p=%u", inb(PORT));

    DHT11_Hi;           //high
    usleep(40);
     //input

    //check start condition 1
    if( DHT11_INP ) {
        printf("\nBlad #1, p=%u", inb(PORT));
        return DHT11_ERROR;
    }

    usleep(80);
    //check start condition 2
    if( !(DHT11_INP )) {
        printf("\nBlad #2");
        return DHT11_ERROR;
    }
    usleep(80);

    //read the data
    for (j=0; j<5; j++) { //read 5 byte

        unsigned result=0;
        for(i=0; i<8; i++) {//read every bit
            while(!( DHT11_INP )); //wait for an high input
            usleep(30);
            if( DHT11_INP ) //if input is high after 30 us, get result
                result |= (1<<(7-i));
            while( DHT11_INP ); //wait until input get low
        }
        bits[j] = result;
    }

    //reset port
    DHT11_Lo;   //low
    usleep(100000);

    //check checksum
    if (bits[0] + bits[1] + bits[2] + bits[3] == bits[4]) {
            temperature=bits[2];
            humidity=bits[0];

    }
    else {
        printf("\nBlad #3");
        return DHT11_ERROR;
    }
}


main(int argc, char **argv)
{

      if (ioperm(PORT, 3, 1))
          printf("ERROR: Can't gain access to port %x\n", PORT);

        dht11_getdata();
        printf("\nTemperatura: %uoC, Wilgotność: %u\n", temperature, humidity);
}

#define PORT    0x378           // Data Port

#define PORTout         PORT            // Data Port
#define PINout  0                       // D0
#define DHT11_Hi outb( inb(PORTout) | 1<<PINout, PORTout)
#define DHT11_Lo outb( inb(PORTout) & ~(1<<PINout), PORTout)

#define PORTin          PORT+1          // Status  Port
#define PINin   6                       // ACK
#define DHT11_INP inb(PORTin) & 1<<PINin