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Wiimote/Extension Controllers (view source)
Revision as of 10:38, 17 June 2009
, 10:38, 17 June 2009→Wii Motion Plus: I posted a couple of hours too late :-(( I discovered this independently, but someone beat me to it. Here's some more details...
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+Initializing the extension with the standard 0x55/0x00 bytes at 0x0(4)4a600f0 and 0x0(4)a600fb (again, instead of 0x(4)a400f0/0x(4)a400fb like a regular extension) shows data changing for a couple seconds, and then stops.
It appears that the 32 bytes from 0x(4)a60020 are, as usual, calibration information, but it is unknown how they work.
−The 128 bytes from 0x(4)a60050 - 0x(4)a600cf change briefly, but seemingly randomly, after the extension is initialized. More examples of this data block changing over time can be found here: [https://docs.google.com/Doc?id=dds4pks_606fmcd6zwt&hl=en Three Data Samples from Wii Motion Plus (Google Doc)]
−Writing 0x04 to 0x04A600FE activates the MotionPlus as the "active" extension. This does 2 things (with no additional initialization):
−* The standard extension identifier at 0x04A400FE now reads 0x04
−* Extension reports now contain MotionPlus data. Format is:
− zz yy xx ZZ YY XX
−where rotation rate about the X axis is XXxx, etc. in a right-handed orientation. Note that I'm not 100% on the least significant bytes, but that seems to be correct, and the format is self-consistent. It is currently unknown how the MotionPlus is automatically detected - this method provides no status report when the MotionPlus is connected. Writing 0x55 to 0x4A400F0, then 0x00 to 0x4A400FB (standard extension init, works fine even with no extension) re-activates the standard extension, if any, plugged into the MotionPlus pass-through port. The development version of the CWiid driver currently implements this method on the motionplus branch: http://abstrakraft.org/cwiid/browser/branches/motionplus/. Additional information on MotionPlus workings and implementation requirements are at http://abstrakraft.org/cwiid/wiki/MotionPlus.
−The combination of 3 linear accelerations with 3 angular rates allows what Nintendo refers to as 1:1 motion tracking, which is another way of saying 6DOF (degrees of freedom) over a short time. It's only valid over short times because of the integration involved to convert accelerations and rates into positions (input errors, when integrated, blow up over time).
−In addition to providing yaw, the gyros also allow the software to tell the difference between orientation and acceleration, which are difficult to tell apart from the accelerometers which measure a mixture of both.
−[http://www.ailive.net/lm2.html Wii Motion Plus Documentation at AiLive]
= Wii Motion Plus =
= Wii Motion Plus =
−The Wii Motion Plus starts off at register 0xA60000 instead of register 0xA40000, because it has its own extension port on the back allowing a Nunchuk for example to be plugged in along with the Wii Motion Plus. BUT it changes to 0xA40000 once it is initialised by writing 04 to 0xa600fe.
+The Wii Motion Plus starts off at register 0xA60000 instead of register 0xA40000, because it has its own extension port on the back allowing a Nunchuk for example to be plugged in along with the Wii Motion Plus. BUT it changes to 0xA40000 once it is activated by writing 04 to 0xa600fe.
−The Wii Motion Plus is first identified by the 6 bytes: 00 00 A6 20 00 05 at register address 0x(4)a600fa (instead of 0x(4)a400fa like a regular extension). Games attempt to detect the Wii Motion Plus by trying to read the two-byte expansion identifier at 0xA600FE (they try up to 3 times). If a Wii Motion Plus is not present then the attempt to read those bytes will fail with error 7.
+The Wii Motion Plus is first identified by the 6 bytes: 00 00 A6 20 00 05 at register address 0x(4)a600fa (instead of 0x(4)a400fa like a regular extension). Games attempt to detect the Wii Motion Plus by trying to read the two-byte expansion identifier at 0xA600FE (they try up to 3 times, then wait 8 seconds, then check again). If a Wii Motion Plus is not present, or it has already been activated, then the attempt to read those bytes will fail with error 7.
+The extension is initialised by writing 0x55 to 0x(4)a600f0. But there is no need to write 00 to 0x(4)a500fb, since Wii games don't do that. While the Motion Plus is initialising, the value at 0x(4)a600f7 changes from 0x02 to 0x04 to 0x08 to 0x0C to 0x0E then stays at 0x0E. There is no need to read this byte, since games don't. While initialising, the 128 bytes from 0x(4)a60050 - 0x(4)a600cf also change briefly, but randomly, after the extension is initialized. More examples of this data block changing over time can be found here: [https://docs.google.com/Doc?id=dds4pks_606fmcd6zwt&hl=en Three Data Samples from Wii Motion Plus (Google Doc)]
+It appears that the 32 bytes from 0x(4)a60020 are, as usual, calibration information, but it is unknown how they work.
+Writing 0x04 to 0x04A600FE activates the MotionPlus as the "active" extension. This does 2 things (with no additional initialization):
+* The standard extension identifier at 0x04A400FE now reads 0x04
+* Extension reports now contain MotionPlus data. Format is:
+ zz yy xx ZZ YY XX
+where rotation rate about the X axis is XXxx, etc. in a right-handed orientation. Note that I'm not 100% on the least significant bytes, but that seems to be correct, and the format is self-consistent. It is currently unknown how the MotionPlus is automatically detected - this method provides no status report when the MotionPlus is connected. Writing 0x55 to 0x4A400F0, then 0x00 to 0x4A400FB (standard extension init, works fine even with no extension) re-activates the standard extension, if any, plugged into the MotionPlus pass-through port. The development version of the CWiid driver currently implements this method on the motionplus branch: http://abstrakraft.org/cwiid/browser/branches/motionplus/. Additional information on MotionPlus workings and implementation requirements are at http://abstrakraft.org/cwiid/wiki/MotionPlus.
+The combination of 3 linear accelerations with 3 angular rates allows what Nintendo refers to as 1:1 motion tracking, which is another way of saying 6DOF (degrees of freedom) over a short time. It's only valid over short times because of the integration involved to convert accelerations and rates into positions (input errors, when integrated, blow up over time).
+In addition to providing yaw, the gyros also allow the software to tell the difference between orientation and acceleration, which are difficult to tell apart from the accelerometers which measure a mixture of both.
+[http://www.ailive.net/lm2.html Wii Motion Plus Documentation at AiLive]
−Reading 0x100 bytes from 0x(4)a60000 produces the following:
Reading 0x100 bytes from 0x(4)a60000 produces the following:
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4a600f0: 55 ff ff ff ff ff ff 10 ff ff 00 00 a6 20 00 05
4a600f0: 55 ff ff ff ff ff ff 10 ff ff 00 00 a6 20 00 05
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−[[Category:Hardware]]
[[Category:Hardware]]