HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 18 posts ] 
Go to page Previous  1, 2
Author Message
PostPosted: Sat Jun 21, 2014 11:07 pm 
Offline
in the industry
User avatar

Joined: Sun Dec 16, 2007 9:33 pm
Posts: 713
Location: Luxembourg / Sweden
We have hacked it and it is NOT a canbus system. The 'consencus' is just a bunch of internet speculation. (It is a frequency (MHz region) modulated pulse code carried over the +-7.4 volt if you want to know). It simply cannot be canbus since canbus by definition needs more than 2 pins....
Typically:
pin 2: CAN-Low (CAN-)
pin 3: GND (Ground)
pin 7: CAN-High (CAN+)
pin 9: CAN V+ (Power)
If it had been canbus, or any other such standard or derivative thereof, it would have been fairly easy to crack using off the shelf analyzers and software. In the automotive industry this is pretty much standard practice. The Shimano system is entirely proprietary and non-standard and much better suited to bicycle application; a canbus system would highly impractical (or useless) in a bicycle since it has to be terminated at each end with 120Ohm resistors and thus draw a lot of power.

_________________
Technical Artisans


Top
 Profile  
 
PostPosted: Sun Jun 22, 2014 2:01 am 
Offline

Joined: Sun May 16, 2010 7:28 pm
Posts: 584
Thanks for sharing your knowledge, I've not touched a di2 system, I'm going entirely off of what others have discussed. If you've analyzed the protocol, can you provide some oscilloscope screenshots to help others decode the Shimano protocol?


Top
 Profile  
 
Posted: Sun Jun 22, 2014 2:01 am 


Top
  
 
PostPosted: Sun Jun 22, 2014 9:26 am 
Offline
in the industry
User avatar

Joined: Sun Dec 16, 2007 9:33 pm
Posts: 713
Location: Luxembourg / Sweden
Errr... No! Shimano would take a dim view of that I'm afraid. We looked into how it worked simply because we felt we could, our knew people that would find out very quickly to be correct;).
We just like to find out how things work. Finding out the workings took less than 30 minutes, the really hard slog is to catalogue the code and learn what impulses do what - to learn the e-tube language. You then need to design and manufacture the electronics for the host processors that broadcast the messages across the system.

_________________
Technical Artisans


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 18 posts ] 
Go to page Previous  1, 2


Who is online

Users browsing this forum: CarlosFerreiro, cwar, Google [Bot] and 35 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. wireless di2

in Road

coppercook62

2

463

Fri Jan 17, 2014 7:52 am

coppercook62 View the latest post

There are no new unread posts for this topic. Converting Wired into Wireless SRM

in Road

Stefano

4

501

Sat Feb 08, 2014 10:14 am

micky View the latest post

There are no new unread posts for this topic. Cannondale Hollowgram Replacement Ideas

[ Go to page: 1, 2 ]

in Road

allenpg

18

1689

Thu Jun 19, 2014 3:44 am

oreoboreo View the latest post


It is currently Sat Jul 26, 2014 1:01 am

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB