JOY(4)

NAME
joy - joystick device driver

SYNOPSIS
To link into the kernel:
device joy

To load as a kernel loadable module:
    kldload joy

#include <sys/joystick.h>

DESCRIPTION
The joystick device driver allows applications to read the status of the PC joystick.

This device may be opened by only one process at a time.

The joystick status is read from a structure via a read() call. The structure is defined in the header file as follows:

    	struct joystick {
    		int x;         /* x position */
    		int y;         /* y position */
    		int b1;	       /* button 1 status */
    		int b2;	       /* button 2 status */
    	};

Positions are typically in the range 0-2000.

  One line perl example:
    perl -e 'open(JOY,"/dev/joy0")||die;while(1)
    {sysread(JOY,$x,16);@j=unpack("iiii",$x);print "@j\n";sleep(1);}'

  ioctl calls
Several ioctl() calls are also available. They take an argument of type int *

JOY_SETTIMEOUT int *limit
    Set the time limit (in microseconds) for reading the joystick status. Setting a value too small may prevent to get correct values for the positions (which are then set to -2147483648), however this can be useful if one is only interested by the buttons status.

JOY_GETTIMEOUT int *limit
    Get the time limit (in microseconds) used for reading the joystick status.

JOY_SET_X_OFFSET int *offset
    Set the value to be added to the X position when reading the joystick status.

JOY_SET_Y_OFFSET int *offset
    Set the value to be added to the Y position when reading the joystick status.

JOY_GET_X_OFFSET int *offset
    Get the value which is added to the X position when reading the joystick status.

JOY_GET_Y_OFFSET int *offset
    Get the value which is added to the Y position when reading the joystick status.

TECHNICAL SPECIFICATIONS
The pinout of the DB-15 connector is as follows:

      1  XY1 (+5v)
      2  Switch 1
      3  X1 (potentiometer #1)
      4  Switch 1 (GND)
      5  Switch 2 (GND)
      6  Y1 (potentiometer #2)
      7  Switch 2
      8  N.C.
      9  XY2 (+5v)
     10  Switch 4
     11  X2 (potentiometer #3)
     12  Switch 3&4 (GND)
     13  Y2 (potentiometer #4)
     14  Switch 3
     15  N.C.

Pots are normally 0-150k variable resistors (0-100k sometimes), and according to the IBM techref, the time is given by Time = 24.2e-6s + 0.011e-6s * R/Ohms

FILES

/dev/joy?
    joystick device files

HISTORY
The joystick driver appeared in FreeBSD 2.0.5.

AUTHORS
Jean-Marc Zucconi <jmz@cabri.obs-besancon.fr>