259 строки
7.5 KiB
Plaintext
259 строки
7.5 KiB
Plaintext
** 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 unsignificant.
|
|
|
|
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 parameteres
|
|
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 ****
|
|
!!! 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 gain ****
|
|
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 www.immerse.com for Immersion Studio, and www.fcoder.com for ComPortSpy.
|
|
|
|
** Author of this document **
|
|
Johann Deneux <johann.deneux@gmail.com>
|
|
Home page at http://www.esil.univ-mrs.fr/~jdeneux/projects/ff/
|
|
|
|
Additions by Vojtech Pavlik.
|
|
|
|
I-Force is trademark of Immersion Corp.
|