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diff --git a/kernel/Documentation/input/iforce-protocol.txt b/kernel/Documentation/input/iforce-protocol.txt new file mode 100644 index 000000000..66287151c --- /dev/null +++ b/kernel/Documentation/input/iforce-protocol.txt @@ -0,0 +1,258 @@ +** 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 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 **** +!!! 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://web.archive.org/web/*/http://www.esil.univ-mrs.fr + +Additions by Vojtech Pavlik. + +I-Force is trademark of Immersion Corp. |