Hygrosens TEMOD-I2C unter Linux (OpenWRT)

#include <glib.h>

#include <glib/gprintf.h>

#include <errno.h>

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <linux/i2c-dev.h>

#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

void main(void) {

    int file;

    int len;

    char filename[40];

    const gchar *buffer;

    int addr = 0x78;        // The I2C address of the ADC

    sprintf(filename,"/dev/i2c-0");

    if ((file = open(filename,O_RDWR)) < 0) {

        perror("Failed to open the bus.");

        /* ERROR HANDLING; you can check errno to see what went wrong */

        exit(1);

    }

    if (ioctl(file,I2C_SLAVE,addr) < 0) {

        perror("Failed to acquire bus access and/or talk to slave.\n");

        /* ERROR HANDLING; you can check errno to see what went wrong */

        exit(1);

    }

    char buf[10] = {0};

    // Using I2C Read

    len=read(file,buf,2);

    if (len != 2) {

        /* ERROR HANDLING: i2c transaction failed */

        printf("Failed to read from the i2c bus: Error %02d, len:  %02d\n", errno, len);

        perror("Failed to read from the i2c bus");

    } else {

        printf("Len: %d, Byte 0: %x, Byte 1: %x\n",len, buf[0], buf[1]);

    }

}

# ./test.o

Failed to read from the i2c bus: Error 06, len:  -1

Failed to read from the i2c bus: No such device or address

# ./test.o

Len: 2, Byte 0: ffffffff, Byte 1: ffffffff

Channel 8 Data:  0.000000