Need help decoding a one wire databus... - Page 2

Chris31 · 03-23-2005, 10:01 PM

Oh there you go.

MrP came to the rescue once again

MrPerfectionest · 03-23-2005, 10:21 PM

I can't tell if that is sarcasm or not

Chris31 · 03-23-2005, 10:27 PM

Your info about that protocol is more complete and plus you have worked on this before.

So its a compliment sir.

Chris31 · 03-23-2005, 10:30 PM

If the low pulse in the init phase is only 2.25ms long it is just a signal send periodical when a key is hold down and there are no data bits.

Dexter have you verified that? I think you will also need to take that condition in mind.

Dexter · 03-23-2005, 10:31 PM

Wow, that is cool info, MrP. Any info is good info, so if you've got some that wouldnt be too much trouble to dig up, that would be cool.

thanks again.

Dexter · 03-23-2005, 10:32 PM

Quote: Originally Posted by Chris31

If the low pulse in the init phase is only 2.25ms long it is just a signal send periodical when a key is hold down and there are no data bits.

Dexter have you verified that? I think you will also need to take that condition in mind.

Low pulse in init phase is always 9ms. I have not ever seen it at 2.25ms.

Chris31 · 03-23-2005, 10:43 PM

Quote: Originally Posted by Dexter

Low pulse in init phase is always 9ms. I have not ever seen it at 2.25ms.

Ok, maybe MrPs info is the complete protocol.

I think you just gonna have to wait for him to give you more infos. Im sure he also got some tips for you in the programming side of things.

MrPerfectionest · 03-23-2005, 11:01 PM

The document I posted was for panasonic CD changers and the one implemented by Mazda may be slightly different. I believe the reason this protocol gets used is because it doesn't have to be licensed (like IC2, etc) and there are a lot of designs and things out there that have used it before and in general it is farily easy to implement.

Generally speaking though, the protocol is the same and you just need to figure out all the useful peices of information in the message (which seems to be just one nibble and its inverse if you want error checking).

JazzyMT · 03-04-2006, 09:09 PM

Wow. I've been looking on the changer protocol for my Subaru Matsu****a/Panasonic radio and if this works, you just saved the day for me!

One difference I know already is the I/O line seems to be working on 3.5V logic in my radio...? Will need to do some more sampling to figure out if they're the same.

I hope this is not too far over my head to follow...