Hi Jan On Tue, 8 Jun 2004, Jan Kiszka wrote:
> Bret Yen-Ting Lin wrote: > > > Hi Jan > > > > The RTmac/TDMA seems to be working now, though I am not entirely sure what > > fixed it .. All I did it play around with the TDMA_CYCLE in the rtnet.conf > > Probably you picked a too short period in your first experiments. > Everything below 1 ms needs special care and adequate performance of the > stations. Indeed, 1ms is the offset i put in the config file. One quick question though, if RTnet is guaranteed with jitter across the network of about few us why would anything below 1ms be a problem ? > > > file. I am glad it is working as expected.. however I am not sure how to > > use Rtnet and TDMA especially. Is there any documentation in how to use > > the API ? > > > > I understand there are examples but maybe what I am looking for is all the > > available APIs/functions that I may use. Most of the examples have little > > comments and is not really making clear of how each function is used and > > related... > > > > Well, the old topic. We still don't have such an overview (hacking > already takes a lot of time...). However, I'm just working on slides > about the API for our developer meeting. They will be published > afterwards, but I can send you a preview soon. > Thank you so much, it would indeed be a great aid to what I am planning to do with it. Thanks in advance. > > For the RTmac/TDMA, do i send packets as a real-time task or user space ? > > You can send packets both from kernel and user space (LXRT), but the > context should be real-time. > > > and which example would be the best user guide? > > > > All demos in /examples run both with and without RTmac/TDMA. Those in > /rtmac/examples (or /examples/rtmac in 0.7.0-testX) are used to > demonstrate the RTmac behaviour (delays due to the cyclic nature) and > its features (time stamping, sync on start of frame). > I browsed all the examples in /rtmac/example and came across several question, hoping you can help me. 1) I see that under TDMA, in order to send packages tdma_wait_sof is firstly called followed by the rt_socket_sendto. Please correctly me if I am wrong, so tdma_wait_sof waits ( process suspend ?) for its turn to transmit in the time slot ? just like how rt_task_wait_period in RTAI is meant to be ? 2) Another question would be, is it be possible that the packet size is too large that slot deadline is breached ? since it is written in LXRT, what happens if the slot is disoriented ? 3) May multiple 'thread' real-time task send packet to the same slot ? Maybe I should say, is it possible to squeeze multiple packet from different tasks to the same cycle slot time? How can I order the packets? > If you want to send UDP messages, take a look at frag_ip or > round_trip_time, for Ethernet packets, examine raw_packets. > > > p.s. what does rtmac/example/mrtt , Event, and rtt stands for ? this > > might aid me in interpreting some of the variable used. > > > > rtt = round trip time (peer-to-peer) > mrtt = multiple rtt (one client to many servers, use server from rtt) > event = compare distributed time stamps of asynchronous external event > (generated by serial or parallel port) Great, this explains much > > Jan > Thanks so much You have been so helpful Bret ------------------------------------------------------- This SF.Net email is sponsored by: GNOME Foundation Hackers Unite! GUADEC: The world's #1 Open Source Desktop Event. GNOME Users and Developers European Conference, 28-30th June in Norway http://2004/guadec.org _______________________________________________ RTnet-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/rtnet-users
