On Sat, 2011-09-24 at 09:39 -0400, Andy Walls wrote: > On Sat, 2011-09-24 at 09:16 -0400, Andy Walls wrote: > > On Fri, 2011-09-23 at 20:43 -0300, Mauro Carvalho Chehab wrote: > > > Em 19-09-2011 08:12, Lawrence Rust escreveu: > > > > The current decoder for the RC6 IR protocol supports mode 0 (16 bit) and > > > > mode 6A. In mode 6A the decoder supports either 32-bit data (for > > > > Microsoft's MCE RC) or 24 bit. > > > > > > > > I would like to support a Sky/Sky+ standard RC which transmits RC6-6-20 > > > > i.e. 20 bit data. The transmitted frame format is identical to the 24 > > > > bit form so I'm curious as to what remotes transmit 24 bit data or was > > > > this an error and it should be 20? > > > > > > > > RC6-6-20 is explained here: > > > > http://www.guiott.com/wrc/RC6-6.html > > > > > > > > If 24-bit mode is in use, is there a way to select between 20 and 24 bit > > > > operation? > > > > > > You'll need to figure out a way to detect between them. It is probably not > > > hard to detect, and add support for both at the decider. > > > Maybe you can find something useful here: > > > http://www.sbprojects.com/knowledge/ir/rc6.php > > > > Lawrence: > > > > Some RC-6 explanations with more detail could be found here: > > > > http://slycontrol.ru/scr/kb/rc6.htm (dead; not in the Wayback machine :( ) > > I found where the above website moved: :) > > http://slydiman.narod.ru/scr/kb/rc6.htm > > -Andy > > > http://www.picbasic.nl/info_rc6_uk.htm > > > > You might also find this thread of interest for some history: > > http://www.spinics.net/lists/linux-input/msg07983.html > > > > The take away is that the data length is, in theory, OEM dependent for > > RC-6 Mode 6A, limited to a max of 24 bits (3 bytes) after a short > > customer code and 128 bits (16 bytes) after a long customer code. > > > > In that previous thread, I suggested it might be better to look for the > > signal free time of 6 RC6_UNITs to declare the end of reception, instead > > of a bit count. Maybe that is a way to deal with the current problem. Andy, Many thanks for the pointers - they confirm that the Sky RC is just using a shortened but permissible form of 24 bit. So your suggestion of looking for a stop sequence is probably the only/best way. In fact it would actually correct the current implementation which assumes a fixed length of 24 or 32 bits. If I wrote a patch that handles variable data lengths (up to 24 or 128 bits) would you be willing to review it? I can test with a Sky RC and I also have a MCEUSB RC on order which should hopefully arrive next week. So that should test the current 32-bit case. -- Lawrence -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
