orange_pi_experiments/i2c.c at master · hxmn/orange_pi_experiments · GitHub

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#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>
#include <ncurses.h> /* sudo apt-get install libncurses5-dev */

int main(int argc, char **argv) {
    int i;
    int r;
    int fd;
    int aout;
    unsigned char command[2];
    unsigned char value[4];
    unsigned char str[8];
    useconds_t delay = 10000;

    char *dev = "/dev/i2c-1";
    int addr = 0x48;

    int j;
    int key;

    initscr();
    noecho();
    cbreak();
    nodelay(stdscr, true);
    curs_set(0);
    printw("PCF8591");

    mvaddstr(10, 0, "Brightness");
    mvaddstr(12, 0, "Temperature");
    mvaddstr(14, 0, "?");
    mvaddstr(16, 0, "Resistor");
    mvaddstr(18, 0, "Output");

    refresh();
    fd = open(dev, O_RDWR);
    if (fd < 0) {
        perror("Opening i2c device node\n");
        return 1;
    }

    r = ioctl(fd, I2C_SLAVE, addr);
    if (r < 0) {
        perror("Selecting i2c device\n");
    }

    command[1] = 0;
    aout = 0;
    while (1) {
        for (i = 0; i < 4; i++) {
//            command[1] = 0;
            command[0] = 0x40 | ((i + 1) & 0x03); // output enable | read input i
            r = write(fd, &command, 2);
            usleep(delay);
            // the read is always one step behind the selected input
            r = read(fd, &value[i], 1);
            if (r != 1) {
                perror("reading i2c device\n");
            }
            usleep(delay);

            sprintf(str, "%3d", value[i]);
            mvaddstr(10 + i + i, 12, str);

            sprintf(str, "%3d", command[1]);
            mvaddstr(18, 12, str);

            value[i] = value[i] / 4;
            move(10 + i + i, 16);

            for (j = 0; j < 64; j++) {
                if (j < value[i]) {
                    addch('*');
                } else {
                    addch(' ');
                }
            }
        }
        refresh();

        key = getch();
        if (key == 43) {
            command[1]+=10;
        } else if (key == 45) {
            command[1]--;
        } else if (key > -1) {
            break;
        }
    }

    endwin();
    close(fd);
    printf("%d\n", key);
    return (0);
}