> There are some compromises we can make here for the sake of pin > savings. For instance, with a 30-bit address bus (plus four write > enables), the upper bits of the address change infrequently. We could > make the address bus 15 bits and have separate transactions for the > upper and lower bits. This way, when streaming data, there's one > upper-half transaction, followed by many lower-halfs. You'll get a > wasted cycle every 128K bytes to change the upper half. This also > gives us some room for optimizing the state machine for higher speeds. > I'll get into the specifics of the hand-shaking, as it progresses. >
Typical bus are horrible because of the read round trip (setup/hold timing, ...). So serial bus is much easier to do with better performance, and less static timing analysis headhack, IMHO. Point to Point connections is the fastest connection. So you could use 32 bits for writing PCI to OGP and 16 bits from the OGP to the PCI chip (with one clock for each way ? So you could sample the input using those clock, and win some more time on the clock jitter and output delay). You have to define some "packet" format which include data and adresse. Basically you need 2 types of paquet one to minimise latency and one to maximise bandwith usage. What do you think of it ? Nicolas Boulay _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
