Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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+===============
+Iforce Protocol
+===============
+
+:Author: Johann Deneux <johann.deneux@gmail.com>
+
+Home page at `<http://web.archive.org/web/*/http://www.esil.univ-mrs.fr>`_
+
+:Additions: by Vojtech Pavlik.
+
+
+Introduction
+============
+
+This document describes what I managed to discover about the protocol used to
+specify force effects to I-Force 2.0 devices.  None of this information comes
+from Immerse. That's why you should not trust what is written in this
+document. This document is intended to help understanding the protocol.
+This is not a reference. Comments and corrections are welcome.  To contact me,
+send an email to: johann.deneux@gmail.com
+
+.. warning::
+
+    I shall not be held responsible for any damage or harm caused if you try to
+    send data to your I-Force device based on what you read in this document.
+
+Preliminary Notes
+=================
+
+All values are hexadecimal with big-endian encoding (msb on the left). Beware,
+values inside packets are encoded using little-endian.  Bytes whose roles are
+unknown are marked ???  Information that needs deeper inspection is marked (?)
+
+General form of a packet
+------------------------
+
+This is how packets look when the device uses the rs232 to communicate.
+
+== == === ==== ==
+2B OP LEN DATA CS
+== == === ==== ==
+
+CS is the checksum. It is equal to the exclusive or of all bytes.
+
+When using USB:
+
+== ====
+OP DATA
+== ====
+
+The 2B, LEN and CS fields have disappeared, probably because USB handles
+frames and data corruption is handled or insignificant.
+
+First, I describe effects that are sent by the device to the computer
+
+Device input state
+==================
+
+This packet is used to indicate the state of each button and the value of each
+axis::
+
+    OP= 01 for a joystick, 03 for a wheel
+    LEN= Varies from device to device
+    00 X-Axis lsb
+    01 X-Axis msb
+    02 Y-Axis lsb, or gas pedal for a wheel
+    03 Y-Axis msb, or brake pedal for a wheel
+    04 Throttle
+    05 Buttons
+    06 Lower 4 bits: Buttons
+       Upper 4 bits: Hat
+    07 Rudder
+
+Device effects states
+=====================
+
+::
+
+    OP= 02
+    LEN= Varies
+    00 ? Bit 1 (Value 2) is the value of the deadman switch
+    01 Bit 8 is set if the effect is playing. Bits 0 to 7 are the effect id.
+    02 ??
+    03 Address of parameter block changed (lsb)
+    04 Address of parameter block changed (msb)
+    05 Address of second parameter block changed (lsb)
+    ... depending on the number of parameter blocks updated
+
+Force effect
+------------
+
+::
+
+    OP=  01
+    LEN= 0e
+    00 Channel (when playing several effects at the same time, each must
+                be assigned a channel)
+    01 Wave form
+	    Val 00 Constant
+	    Val 20 Square
+	    Val 21 Triangle
+	    Val 22 Sine
+	    Val 23 Sawtooth up
+	    Val 24 Sawtooth down
+	    Val 40 Spring (Force = f(pos))
+	    Val 41 Friction (Force = f(velocity)) and Inertia
+	           (Force = f(acceleration))
+
+
+    02 Axes affected and trigger
+	    Bits 4-7: Val 2 = effect along one axis. Byte 05 indicates direction
+		    Val 4 = X axis only. Byte 05 must contain 5a
+		    Val 8 = Y axis only. Byte 05 must contain b4
+		    Val c = X and Y axes. Bytes 05 must contain 60
+	    Bits 0-3: Val 0 = No trigger
+		    Val x+1 = Button x triggers the effect
+	    When the whole byte is 0, cancel the previously set trigger
+
+    03-04 Duration of effect (little endian encoding, in ms)
+
+    05 Direction of effect, if applicable. Else, see 02 for value to assign.
+
+    06-07 Minimum time between triggering.
+
+    08-09 Address of periodicity or magnitude parameters
+    0a-0b Address of attack and fade parameters, or ffff if none.
+    *or*
+    08-09 Address of interactive parameters for X-axis,
+          or ffff if not applicable
+    0a-0b Address of interactive parameters for Y-axis,
+	  or ffff if not applicable
+
+    0c-0d Delay before execution of effect (little endian encoding, in ms)
+
+
+Time based parameters
+---------------------
+
+Attack and fade
+^^^^^^^^^^^^^^^
+
+::
+
+    OP=  02
+    LEN= 08
+    00-01 Address where to store the parameters
+    02-03 Duration of attack (little endian encoding, in ms)
+    04 Level at end of attack. Signed byte.
+    05-06 Duration of fade.
+    07 Level at end of fade.
+
+Magnitude
+^^^^^^^^^
+
+::
+
+    OP=  03
+    LEN= 03
+    00-01 Address
+    02 Level. Signed byte.
+
+Periodicity
+^^^^^^^^^^^
+
+::
+
+    OP=  04
+    LEN= 07
+    00-01 Address
+    02 Magnitude. Signed byte.
+    03 Offset. Signed byte.
+    04 Phase. Val 00 = 0 deg, Val 40 = 90 degs.
+    05-06 Period (little endian encoding, in ms)
+
+Interactive parameters
+----------------------
+
+::
+
+    OP=  05
+    LEN= 0a
+    00-01 Address
+    02 Positive Coeff
+    03 Negative Coeff
+    04+05 Offset (center)
+    06+07 Dead band (Val 01F4 = 5000 (decimal))
+    08 Positive saturation (Val 0a = 1000 (decimal) Val 64 = 10000 (decimal))
+    09 Negative saturation
+
+The encoding is a bit funny here: For coeffs, these are signed values. The
+maximum value is 64 (100 decimal), the min is 9c.
+For the offset, the minimum value is FE0C, the maximum value is 01F4.
+For the deadband, the minimum value is 0, the max is 03E8.
+
+Controls
+--------
+
+::
+
+    OP=  41
+    LEN= 03
+    00 Channel
+    01 Start/Stop
+	    Val 00: Stop
+	    Val 01: Start and play once.
+	    Val 41: Start and play n times (See byte 02 below)
+    02 Number of iterations n.
+
+Init
+----
+
+
+Querying features
+^^^^^^^^^^^^^^^^^
+::
+
+    OP=  ff
+    Query command. Length varies according to the query type.
+    The general format of this packet is:
+    ff 01 QUERY [INDEX] CHECKSUM
+    responses are of the same form:
+    FF LEN QUERY VALUE_QUERIED CHECKSUM2
+    where LEN = 1 + length(VALUE_QUERIED)
+
+Query ram size
+~~~~~~~~~~~~~~
+
+::
+
+    QUERY = 42 ('B'uffer size)
+
+The device should reply with the same packet plus two additional bytes
+containing the size of the memory:
+ff 03 42 03 e8 CS would mean that the device has 1000 bytes of ram available.
+
+Query number of effects
+~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    QUERY = 4e ('N'umber of effects)
+
+The device should respond by sending the number of effects that can be played
+at the same time (one byte)
+ff 02 4e 14 CS would stand for 20 effects.
+
+Vendor's id
+~~~~~~~~~~~
+
+::
+
+    QUERY = 4d ('M'anufacturer)
+
+Query the vendors'id (2 bytes)
+
+Product id
+~~~~~~~~~~
+
+::
+
+    QUERY = 50 ('P'roduct)
+
+Query the product id (2 bytes)
+
+Open device
+~~~~~~~~~~~
+
+::
+
+    QUERY = 4f ('O'pen)
+
+No data returned.
+
+Close device
+~~~~~~~~~~~~
+
+::
+
+    QUERY = 43 ('C')lose
+
+No data returned.
+
+Query effect
+~~~~~~~~~~~~
+
+::
+
+    QUERY = 45 ('E')
+
+Send effect type.
+Returns nonzero if supported (2 bytes)
+
+Firmware Version
+~~~~~~~~~~~~~~~~
+
+::
+
+    QUERY = 56 ('V'ersion)
+
+Sends back 3 bytes - major, minor, subminor
+
+Initialisation of the device
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Set Control
+~~~~~~~~~~~
+
+.. note::
+    Device dependent, can be different on different models!
+
+::
+
+    OP=  40 <idx> <val> [<val>]
+    LEN= 2 or 3
+    00 Idx
+       Idx 00 Set dead zone (0..2048)
+       Idx 01 Ignore Deadman sensor (0..1)
+       Idx 02 Enable comm watchdog (0..1)
+       Idx 03 Set the strength of the spring (0..100)
+       Idx 04 Enable or disable the spring (0/1)
+       Idx 05 Set axis saturation threshold (0..2048)
+
+Set Effect State
+~~~~~~~~~~~~~~~~
+
+::
+
+    OP=  42 <val>
+    LEN= 1
+    00 State
+       Bit 3 Pause force feedback
+       Bit 2 Enable force feedback
+       Bit 0 Stop all effects
+
+Set overall
+~~~~~~~~~~~
+
+::
+
+    OP=  43 <val>
+    LEN= 1
+    00 Gain
+       Val 00 = 0%
+       Val 40 = 50%
+       Val 80 = 100%
+
+Parameter memory
+----------------
+
+Each device has a certain amount of memory to store parameters of effects.
+The amount of RAM may vary, I encountered values from 200 to 1000 bytes. Below
+is the amount of memory apparently needed for every set of parameters:
+
+ - period : 0c
+ - magnitude : 02
+ - attack and fade : 0e
+ - interactive : 08
+
+Appendix: How to study the protocol?
+====================================
+
+1. Generate effects using the force editor provided with the DirectX SDK, or
+use Immersion Studio (freely available at their web site in the developer section:
+www.immersion.com)
+2. Start a soft spying RS232 or USB (depending on where you connected your
+joystick/wheel). I used ComPortSpy from fCoder (alpha version!)
+3. Play the effect, and watch what happens on the spy screen.
+
+A few words about ComPortSpy:
+At first glance, this software seems, hum, well... buggy. In fact, data appear with a
+few seconds latency. Personally, I restart it every time I play an effect.
+Remember it's free (as in free beer) and alpha!
+
+URLS
+====
+
+Check http://www.immerse.com for Immersion Studio,
+and http://www.fcoder.com for ComPortSpy.
+
+
+I-Force is trademark of Immersion Corp.