/dev/joy?
joystick device files
joy4
Joystick device driver
Usage
To link into the kernel: device joy
To load as a kernel loadable module:
kldload joy
In /boot/device.hints: hint.joy.0.at="isa" hint.joy.0.port="0x201"
#include <sys/joystick.h>
Overview
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 follow:
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