Failed to receive the answer (from Suunto Vyper Air)
jefdriesen at telenet.be
Wed Jun 20 06:10:46 PDT 2012
On 2012-06-20 14:45, Amit Chaudhuri wrote:
>> If the failure is during the first data packet, then this is a known
>> with the vyper2 class devices. For some unknown reason the
>> to startup properly the first time you try, but if you retry
>> it usually works. Unfortunately we don't know what the underlying
>> is. It
>> might indeed be some timing issue. If anyone has some suggestions,
>> let me
> Tried the immediate retry idea (thanks) and it consistently fails.
> I will add some diagnostics to libdivecomputer and recompile &
> I'll update in a few days with any results.
> If you have any suggestions for other things I might try I'm open to
> a tinker. I've no experience of reverse engineering protocols but I
> am not
> afraid of a bit of research and some C/C++.
If you need additional diagnostics, apply this patch  to log the
serial communication. This will allow you to see what is going on. The
same patch is also used in the pre-compiled test applications on the
If you need some info on the protocol look here .
Possible areas of interest are the serial_sleep calls (especially the
one at startup, try to make it larger) and the half-duplex emulation
(which is basically a variable length sleep).
More information about the subsurface