nunchuck_read_curses.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <ncurses.h>

#define NUNCHUCK_ADDR 0x52  // Wii Nunchuck I2C address

// Function prototypes
void nunchuck_init(int file);
void nunchuck_read(int file, unsigned char *data);
void print_data(unsigned char *data, int row);

int main() {
    const char *device = "/dev/i2c-1";
    int file;

    if ((file = open(device, O_RDWR)) < 0) {
        perror("Failed to open the I2C device");
        return 1;
    }

    if (ioctl(file, I2C_SLAVE, NUNCHUCK_ADDR) < 0) {
        perror("Failed to acquire bus access and/or talk to slave");
        return 1;
    }

    // Initialize Nunchuck
    nunchuck_init(file);

    // Initialize ncurses
    initscr();              // Start ncurses
    cbreak();               // Disable line buffering
    noecho();               // Don't echo key presses
    timeout(0);             // Non-blocking getch
    keypad(stdscr, TRUE);   // Enable keypad input
    curs_set(0);            // Hide cursor

    int row = 0;  // Track current row for printing data

    // Print initial UI headers
    printw("Wii Nunchuck Data:\n\n");
    printw("  Z Button | C Button | Joystick X | Joystick Y | Accel X | Accel Y | Accel Z\n");
    printw("------------------------------------------------------------------------------\n");

    refresh();  // Refresh the screen

    unsigned char data[6];

    while (1) {
        // Read data from Nunchuck
        nunchuck_read(file, data);

        // Print data in UI format
        print_data(data, row);

        // Move to the next row
        row++;

        // Check if we've reached the end of the screen
        if (row >= LINES - 3) {
            // Clear screen and reset row count
            clear();
            row = 0;

            // Print headers again
            printw("Wii Nunchuck Data:\n\n");
            printw("  Z Button | C Button | Joystick X | Joystick Y | Accel X | Accel Y | Accel Z\n");
            printw("------------------------------------------------------------------------------\n");
        }

        refresh();  // Refresh the screen
        usleep(100000);  // Sleep for 100ms
    }

    // End ncurses
    endwin();
    close(file);
    return 0;
}

void nunchuck_init(int file) {
    unsigned char buf[2];
    buf[0] = 0xF0;
    buf[1] = 0x55;
    if (write(file, buf, 2) != 2) {
        perror("Failed to initialize Nunchuck");
        exit(1);
    }
    usleep(5000);
    buf[0] = 0xFB;
    buf[1] = 0x00;
    if (write(file, buf, 2) != 2) {
        perror("Failed to initialize Nunchuck");
        exit(1);
    }
}

void nunchuck_read(int file, unsigned char *data) {
    if (write(file, NULL, 0) != 0) {
        perror("Failed to request data from Nunchuck");
        exit(1);
    }
    usleep(5000);
    if (read(file, data, 6) != 6) {
        perror("Failed to read data from Nunchuck");
        exit(1);
    }
}

void print_data(unsigned char *data, int row) {
    // Extract button states
    int z_btn = !(data[5] & 0x01);
    int c_btn = !(data[5] & 0x02);

    // Move cursor to the specified row and column
    move(row + 4, 0);

    // Print data in UI format
    printw("   %s   |   %s   |    %3d     |    %3d     |   %3d   |   %3d   |   %3d\n",
           z_btn ? "ON " : "OFF", c_btn ? "ON " : "OFF", data[0], data[1], data[2], data[3], data[4]);
}