Re: [Xenomai-help] RTCAN and tsc

[Wolfgang Grandegger <wg@domain.hid>]

Daniel Schnell wrote:
> roland Tollenaar wrote:
>> What baffles me a bit  then is that the behavior cannot be classified
>> as very "Real-Time" can it?     
> 
> Real-Time does mean the system reacts in time. There is nothing a
> software can do if the hardware is not meeting your requirements of
> beeing in time. Having reliable 0.5 ms real-time is e.g. for us
> absolutely real-time and we chose carefully our hardware components that
> this will never be exceeded. For us Xenomai and RTCAN on a MPC5200B
> platform do a good job.
> 
>  I cannot imagine that the developers of
>> rt-can overlooked this. I doubt that it will be possible to run a
>> discrete state-space controller successfully on a platform that
>> juggles around its period-times as badly as I am experiencing. And I
>> still need to read discrete IO and write DIO and AIO to another CAN
>> node which is not yet even connected.
> 
> Choose your hardware carefully. Parallel port CANS are certainly much
> slower than e.g. PCI adapters. On a Laptop you have the possibility to
> add e.g. PCCARD CAN. But before purchasing I would check how these are
> supported and which typical access times you can expect. USB CAN is
> certainly even slower, so this will be no option.

To confirm that, the PCAN dongle is a nice cheap device for low CAN 
speeds but not appropriate for 1MB/s. Please ask PEAK for more detailed 
information (e.g. linux@domain.hid).

Wolfgang.