[A83] Re: calculator networking - good idea?
[Prev][Next][Index][Thread]
[A83] Re: calculator networking - good idea?
> It looks good. I miss some details though. One thing is that a calc that
> wants to initiate to send, should wait for the line to be silent.
> maybe you thought of that, but didn't write it, but anyway.
> This is specially critical i this design, since only the calc already
> sending can detect collision.
> Otherwise you probably would have several calcs working their asses off
> trying to send data, but no data is actually sent, because they get
> interrupted by another calc after just a few bytes and has to start
> over, in the meantime the interrupting calc has just succeded in sending
> its first bytes of data, and gets interrupted by the first, and so on...
You're right. I was going to include something where if both lines are high
for a specified amount of time (a *random* value from 800 to 1500
microseconds [by clock cycles] or so) a calculator is free to attempt to
send. Because in both of my transfer routines, at least one line is brought
low at every bit.
> You should probably make the delays random too (a simple fast one is
> enough), so that two calcs won't wait the same time all the time,
> specially at collisions, and in waiting for the line to be silent, to
> avoid having calcs try att the approximate same time.
> (Due to murphys laws, the calcs will very often try to send at the exact
> same time, regardless of how unsyncronized they are. Probably no matter
> what you do, too, but some measures can be taken.:)
That's good. Random delays in waiting for the lines to be silent and in
initiating transfers would be extremely helpful.
Thanks!
Jeff
References: