On Tue, 7 Jun 2005 16:29:56 -0400 Timothy Miller <[EMAIL PROTECTED]> wrote:
> http://opengraphics.gitk.com/sync.gif Looks nice, but as it always passes the token around, we'll have an additional delay when new data arrives until the token passes from the first clock domain to the second. Moreover, this delay is prety much random, depending on where the token currently is and as it passes the clock domain border twice, we can have an additional delay of c1+c2 in the worst case (ie when on both border crossings of the token the timing constraints are violated and thus a metastable state is created) How about using an req/ack system ? Ie the first clock domain sets his req line to signal that there is new data to fetch, the second clock domain fetches the data on seeing the req signal assertion, and after it ensured that all data has been copied correctly, it sets the ack line, signaling that it got everything. Another system that could be used is, to add an additional register on the side of the second clock domain and compare it's input and ouptut, if it differs, we are in the transition between two data items and thus have to wait for another clock cylce. Ofcourse this only works if the rate of arriving data items is much lower than the clock of the second domain. Attila Kinali -- 郷に入れば郷に従え _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
