joystick-parport.txt

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

		    Linux Joystick parport drivers v2.0
	       (c) 1998-2000 Vojtech Pavlik <[e-mail]>
	       (c) 1998 Andree Borrmann <[e-mail]>
			     Sponsored by SuSE
	$Id: joystick-parport.txt,v 1.5 2001/05/15 06:41:00 vojtech Exp $
----------------------------------------------------------------------------

0. Disclaimer
~~~~~~~~~~~~~
  Any information in this file is provided as-is, without any guarantee that
it will be true. So, use it at your own risk. The possible damages that can
happen include burning your parallel port, and/or the sticks and joystick
and maybe even more. Like when a lightning kills you it is not our problem.

1. Intro
~~~~~~~~
  The joystick parport drivers are used for joysticks and gamepads not
originally designed for PCs and other computers Linux runs on. Because of
that, PCs usually lack the right ports to connect these devices to. Parallel
port, because of its ability to change single bits at will, and providing
both output and input bits is the most suitable port on the PC for
connecting such devices.

2. Devices supported
~~~~~~~~~~~~~~~~~~~~
  Many console and 8-bit computer gamepads and joysticks are supported. The
following subsections discuss usage of each.

2.1 NES and SNES
~~~~~~~~~~~~~~~~
  The Nintendo Entertainment System and Super Nintendo Entertainment System
gamepads are widely available, and easy to get. Also, they are quite easy to
connect to a PC, and don't need much processing speed (108 us for NES and
165 us for SNES, compared to about 1000 us for PC gamepads) to communicate
with them.

  All NES and SNES use the same synchronous serial protocol, clocked from
the computer's side (and thus timing insensitive). To allow up to 5 NES
and/or SNES gamepads connected to the parallel port at once, the output
lines of the parallel port are shared, while one of 5 available input lines
is assigned to each gamepad.

  This protocol is handled by the gamecon.c driver, so that's the one
you'll use for NES and SNES gamepads.

  The main problem with PC parallel ports is that they don't have +5V power
source on any of their pins. So, if you want a reliable source of power
for your pads, use either keyboard or joystick port, and make a pass-through
cable. You can also pull the power directly from the power supply (the red
wire is +5V).

  If you want to use the parallel port only, you can take the power is from
some data pin. For most gamepad and parport implementations only one pin is
needed, and I'd recommend pin 9 for that, the highest data bit. On the other
hand, if you are not planning to use anything else than NES / SNES on the
port, anything between and including pin 4 and pin 9 will work.

(pin 9) -----> Power

  Unfortunately, there are pads that need a lot more of power, and parallel
ports that can't give much current through the data pins. If this is your
case, you'll need to use diodes (as a prevention of destroying your parallel
port), and combine the currents of two or more data bits together.

	   Diodes
(pin 9) ----|>|-------+------> Power
		      |
(pin 8) ----|>|-------+
		      |
(pin 7) ----|>|-------+
		      |
 <and so on>          :
		      |
(pin 4) ----|>|-------+

  Ground is quite easy. On PC's parallel port the ground is on any of the
pins from pin 18 to pin 25. So use any pin of these you like for the ground.

(pin 18) -----> Ground

  NES and SNES pads have two input bits, Clock and Latch, which drive the
serial transfer. These are connected to pins 2 and 3 of the parallel port,
respectively.

(pin 2) -----> Clock
(pin 3) -----> Latch

  And the last thing is the NES / SNES data wire. Only that isn't shared and
each pad needs its own data pin. The parallel port pins are:

(pin 10) -----> Pad 1 data
(pin 11) -----> Pad 2 data
(pin 12) -----> Pad 3 data
(pin 13) -----> Pad 4 data
(pin 15) -----> Pad 5 data

  Note that pin 14 is not used, since it is not an input pin on the parallel
port.

  This is everything you need on the PC's side of the connection, now on to
the gamepads side. The NES and SNES have different connectors. Also, there
are quite a lot of NES clones, and because Nintendo used proprietary
connectors for their machines, the cloners couldn't and used standard D-Cannon
connectors. Anyway, if you've got a gamepad, and it has buttons A, B, Turbo
A, Turbo B, Select and Start, and is connected through 5 wires, then it is
either a NES or NES clone and will work with this connection. SNES gamepads
also use 5 wires, but have more buttons. They will work as well, of course.

Pinout for NES gamepads                 Pinout for SNES gamepads

	   +----> Power                   +-----------------------\
	   |                            7 | o  o  o  o |  x  x  o  | 1
 5 +---------+  7                         +-----------------------/
   | x  x  o   \                            |  |  |  |          |
   | o  o  o  o |                           |  |  |  |          +-> Ground
 4 +------------+ 1                         |  |  |  +------------> Data
     |  |  |  |                             |  |  +---------------> Latch
     |  |  |  +-> Ground                    |  +------------------> Clock
     |  |  +----> Clock                     +---------------------> Power
     |  +-------> Latch
     +----------> Data

Pinout for NES clone (db9) gamepads     Pinout for NES clone (db15) gamepads

	+---------> Clock                    +-----------------> Data
	| +-------> Latch                    |             +---> Ground
	| | +-----> Data                     |             |
	| | |                              ___________________
    _____________                        8 \ o x x x x x x o / 1
  5 \ x o o o x / 1                         \ o x x o x x o /
     \ x o x o /                          15 `~~~~~~~~~~~~~' 9
    9 `~~~~~~~' 6                             |     |     |
	 |   |                                |     |     +----> Clock
	 |   +----> Power                     |     +----------> Latch
	 +--------> Ground                    +----------------> Power

2.2 Multisystem joysticks
~~~~~~~~~~~~~~~~~~~~~~~~~
  In the era of 8-bit machines, there was something like de-facto standard
for joystick ports. They were all digital, and all used D-Cannon 9 pin
connectors (db9). Because of that, a single joystick could be used without
hassle on Atari (130, 800XE, 800XL, 2600, 7200), Amiga, Commodore C64,
Amstrad CPC, Sinclair ZX Spectrum and many other machines. That's why these
joysticks are called "Multisystem".

  Now their pinout:

      +---------> Right
      | +-------> Left
      | | +-----> Down
      | | | +---> Up
      | | | |
  _____________
5 \ x o o o o / 1
   \ x o x o /
  9 `~~~~~~~' 6
       |   |
       |   +----> Button
       +--------> Ground

  However, as time passed, extensions to this standard developed, and these
were not compatible with each other:


	Atari 130, 800/XL/XE		   MSX

					 +-----------> Power
      +---------> Right                  | +---------> Right
      | +-------> Left                   | | +-------> Left
      | | +-----> Down                   | | | +-----> Down
      | | | +---> Up                     | | | | +---> Up
      | | | |                            | | | | |
  _____________                        _____________
5 \ x o o o o / 1                    5 \ o o o o o / 1
   \ x o o o /                          \ o o o o /
  9 `~~~~~~~' 6                        9 `~~~~~~~' 6
       | | |                              | | | |
       | | +----> Button                  | | | +----> Button 1
       | +------> Power                   | | +------> Button 2
       +--------> Ground                  | +--------> Output 3
					  +----------> Ground

	Amstrad CPC			   Commodore C64

					 +-----------> Analog Y
      +---------> Right                  | +---------> Right
      | +-------> Left                   | | +-------> Left
      | | +-----> Down                   | | | +-----> Down
      | | | +---> Up                     | | | | +---> Up
      | | | |                            | | | | |
  _____________                        _____________
5 \ x o o o o / 1                    5 \ o o o o o / 1
   \ x o o o /                          \ o o o o /
  9 `~~~~~~~' 6                        9 `~~~~~~~' 6
       | | |                              | | | |
       | | +----> Button 1                | | | +----> Button
       | +------> Button 2                | | +------> Power
       +--------> Ground                  | +--------> Ground
					  +----------> Analog X

	Sinclair Spectrum +2A/+3           Amiga 1200
                                     
    +-----------> Up                     +-----------> Button 3
    | +---------> Fire                   | +---------> Right
    | |                                  | | +-------> Left
    | |   +-----> Ground                 | | | +-----> Down
    | |   |                              | | | | +---> Up
    | |   |                              | | | | |
  _____________                        _____________
5 \ o o x o x / 1                    5 \ o o o o o / 1
   \ o o o o /                          \ o o o o /
  9 `~~~~~~~' 6                        9 `~~~~~~~' 6
     | | | |                              | | | |
     | | | +----> Right                   | | | +----> Button 1
     | | +------> Left                    | | +------> Power
     | +--------> Ground                  | +--------> Ground
     +----------> Down                    +----------> Button 2

  And there were many others.

2.2.1 Multisystem joysticks using db9.c
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  For the Multisystem joysticks, and their derivatives, the db9.c driver
was written. It allows only one joystick / gamepad per parallel port, but
the interface is easy to build and works with almost anything.

  For the basic 1-button Multisystem joystick you connect its wires to the
parallel port like this:

(pin  1) -----> Power
(pin 18) -----> Ground

(pin  2) -----> Up
(pin  3) -----> Down
(pin  4) -----> Left
(pin  5) -----> Right
(pin  6) -----> Button 1

  However, if the joystick is switch based (eg. clicks when you move it),
you might or might not, depending on your parallel port, need 10 kOhm pullup
resistors on each of the direction and button signals, like this:

(pin 2) ------------+------> Up
	  Resistor  |
(pin 1) --[10kOhm]--+

  Try without, and if it doesn't work, add them. For TTL based joysticks /
gamepads the pullups are not needed.

  For joysticks with two buttons you connect the second button to pin 7 on
the parallel port.

(pin 7) -----> Button 2

  And that's it.

  On a side note, if you have already built a different adapter for use with
the digital joystick driver 0.8.0.2, this is also supported by the db9.c
driver, as device type 8. (See section 3.2)

2.2.2 Multisystem joysticks using gamecon.c
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  For some people just one joystick per parallel port is not enough, and/or
want to use them on one parallel port together with NES/SNES/PSX pads. This is
possible using the gamecon.c. It supports up to 5 devices of the above types,
including 1 and 2 buttons Multisystem joysticks.