> > Hello, > > > > I read the TDMA-spec and I understood it in general, but thinking > > about some details. What I don't understand is, how the so called > > 'normal startup' is performed. > > > > If a new client comes into RTnet, his clock isn't synchronized to > > master's one. So it means, it neither knows t_offs nor t_trans. > > > > So what it does is waiting for master's sync frame, which contains > > T_sched and T_xmit. So slave can calculate master's jitter from this > > values. > > > > The problem is, to calculate t_trans, slave must send calibration > > request in its time slot. But how can it now when this is, if its > > clock isn't synchronized yet? To synchronize its clock, slave needs > > t_offs, but this is calculated with respect to t_trans. > > > > So my question is, how does slave knows when to send calibration > > request frame? Or is it sending it with CSMA/CD discipline which of > > course destroys any realtime for some time, cause it can cause > > collisions on bus? > > t_trans is set to 0 until the calibration has been performed. As > indicated earlier, that will cause a slight but typically uncritical > delay of the small calibration frames. The network designer has to take > this into account by keeping an appropriate distance to the succeeding > slot. > > Jan >
Sorry, you mentioned this already in another context, I forgot. Thanks for the quick answer. Maybe this should be written in TDMA-spec, too? Cause to my mind this is an important part to understand the whole thing completely. Karl -- von Karl Reichert "Feel free" - 10 GB Mailbox, 100 FreeSMS/Monat ... Jetzt GMX TopMail testen: http://www.gmx.net/de/go/topmail ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ RTnet-users mailing list RTnet-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rtnet-users
