joy.4 revision 12695 
1.Dd January 23, 1995
2.Dt JOY 4
3.Sh NAME
4.Nm joy
5.Nd joystick device driver
6.Sh SYNOPSIS
7.Cd device joy0 at isa? port "IO_GAME"
8.Fd #include <machine/joystick.h>
9.Sh DESCRIPTION
10The joystick device driver allows applications to read the status of
11the PC joystick.
12.Pp
13This device may be opened by only one process at a time.
14.Pp
15The joystick status is get in an structure joystick via a read()
16call. The structure is defined in the header file as follows:
17.Pp
18.Bd -literal -offset indent
19	struct joystick {
20		int x;         /* x position */
21		int y;         /* y position */
22		int b1;	       /* button 1 status */
23		int b2;	       /* button 2 status */
24	};
25.Ed
26.Pp
27Positions are typically in the range 0-2000.
28.Ss One line perl example:
29perl -e 'open(JOY,"/dev/joy0")||die;while(1)
30.br
31{sysread(JOY,$x,16);@j=unpack("iiii",$x);print "@j\\n";sleep(1);}'
32.Ss ioctl calls
33Several ioctl() calls are also available. They take an argument of
34type int *
35.Bl -tag -width JOY_SET_X_OFFSET 
36.It Dv JOY_SETTIMEOUT Fa int *limit
37Set the time limit (in microseconds) for reading the joystick
38status. Setting a value
39too small may prevent to get correct values for the positions (which
40are then set to -2147483648), however this can be useful if one is
41only interested by the buttons status. 
42.It Dv JOY_GETTIMEOUT Fa int *limit
43Get the time limit (in microseconds) used for reading the joystick
44status. 
45.It Dv JOY_SET_X_OFFSET Fa int *offset
46Set the value to be added to the X position  when reading the joystick
47status. 
48.It Dv JOY_SET_Y_OFFSET Fa int *offset
49Set the value to be added to the Y position  when reading the joystick
50status. 
51.It Dv JOY_GET_X_OFFSET Fa int *offset
52Get the value which is added to the X position  when reading the joystick
53status. 
54.It Dv JOY_GET_Y_OFFSET Fa int *offset
55Get the value which is added to the Y position  when reading the joystick
56status. 
57
58.Sh TECHNICAL SPECIFICATIONS
59
60The pinout of the DB-15 connector is as follow:
61.Pp
62  1  XY1 (+5v)
63  2  Switch 1
64  3  X1 (potentiometer #1)
65  4  Switch 1 (GND)
66  5  Switch 2 (GND)
67  6  Y1 (potentiometer #2)
68  7  Switch 2
69  8  N.C.
70  9  XY2 (+5v)
71 10  Switch 4
72 11  X2 (potentiometer #3)
73 12  Switch 3&4 (GND)
74 13  Y2 (potentiometer #4)
75 14  Switch 3
76 15  N.C.
77.Pp
78Pots are normally 0-150k variable resistors (0-100k sometimes), and
79according to the IBM techref, the time is given by
80Time = 24.2e-6s + 0.011e-6s * R/Ohms
81
82.Sh FILES
83.Bl -tag -width /dev/joy?
84.It Pa /dev/joy?
85joystick device files
86.Sh AUTHOR
87Jean-Marc Zucconi <jmz@cabri.obs-besancon.fr>
88.Sh HISTORY
89The joystick driver appeared in FreeBSD 2.0.5.
90