.\"
.\" $FreeBSD$
.\"
.Dd January 23, 1995
.Dt JOY 4
.Os
.Sh NAME
.Nm joy
.Nd joystick device driver
.Sh SYNOPSIS
To link into the kernel:
.Cd device joy
.Pp
To load as a kernel loadable module:
.Dl kldload joy
.Pp
.Fd #include <machine/joystick.h>
.Sh DESCRIPTION
The joystick device driver allows applications to read the status of
the PC joystick.
.Pp
This device may be opened by only one process at a time.
.Pp
The joystick status is read from a structure via a read()
call.
The structure is defined in the header file as follows:
.Pp
.Bd -literal -offset indent
	struct joystick {
		int x;         /* x position */
		int y;         /* y position */
		int b1;	       /* button 1 status */
		int b2;	       /* button 2 status */
	};
.Ed
.Pp
Positions are typically in the range 0-2000.
.Ss One line perl example:
.Bd -literal -compact
perl -e 'open(JOY,"/dev/joy0")||die;while(1)
{sysread(JOY,$x,16);@j=unpack("iiii",$x);print "@j\\n";sleep(1);}'
.Ed
.Ss ioctl calls
Several ioctl() calls are also available.
They take an argument of
type int *
.Bl -tag -width JOY_SET_X_OFFSET 
.It Dv JOY_SETTIMEOUT Fa 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. 
.It Dv JOY_GETTIMEOUT Fa int *limit
Get the time limit (in microseconds) used for reading the joystick
status. 
.It Dv JOY_SET_X_OFFSET Fa int *offset
Set the value to be added to the X position  when reading the joystick
status. 
.It Dv JOY_SET_Y_OFFSET Fa int *offset
Set the value to be added to the Y position  when reading the joystick
status. 
.It Dv JOY_GET_X_OFFSET Fa int *offset
Get the value which is added to the X position  when reading the joystick
status. 
.It Dv JOY_GET_Y_OFFSET Fa int *offset
Get the value which is added to the Y position  when reading the joystick
status. 
.El
.Sh TECHNICAL SPECIFICATIONS
The pinout of the DB-15 connector is as follow:
.Bd -literal
  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.
.Ed
.Pp
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
.Sh FILES
.Bl -tag -width /dev/joy?
.It Pa /dev/joy?
joystick device files
.El
.Sh AUTHORS
.An Jean-Marc Zucconi Aq jmz@cabri.obs-besancon.fr
.Sh HISTORY
The joystick driver appeared in
.Fx 2.0.5 .