Re: [RTnet-users] Problems setting up RT network

[Jan K. <ki...@rt...>]

Jan Kiszka wrote:
>> ...
>> Also on my MPC860 module I see large calibrated master-to-slave packet
>> delays. 440 seconds, this looks like an endianess problem or a wrong
>> (64-bit?) calculation.
>>
> 
> Oops. Ok, let's wait for the binary dump - and what Ethereal dissects.
> 

The dump revealed that there is some problem on the master side (you can
 follow this explanations by opening your dump in a recent Ethereal):

The slave sends its calibration requests including a "Transmission Time
Stamp". This value should be copied by the master on reception into the
calibration reply frame ("Request Transmission Time"). For unknown
reasons, this field is always 0 in your dump. All systems I tested so
far did not show this effect (ok, all were x86). It immediately leads to
such exorbitant round-trip delays.

Could you try to debug this further? The involved code in the TDMA
module can be found here:

http://www.rts.uni-hannover.de/rtnet/lxr/source/stack/rtmac/tdma/tdma_proto.c#L261

The copy is performed in line 297. Please check if the value is
correctly transfered and probably overwritten afterwards (in the 3com
driver?) or if 0 is already contained in the reply frame.

Thanks again for your help,
Jan