Re: Timing in Synch Comm.


"Rich Grise" <rich@xxxxxxxxxxx> wrote in message
news:pan.2007.09.20.23.04.33.168563@xxxxxxxxxxxxxx
On Thu, 20 Sep 2007 22:30:21 +0000, Jon Slaughter wrote:
"Joerg" <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote in message
...
I believe the OP wasn't talking about SPI. But with SPI you are right.
Many devices, even simple DACs and ADCs have time-out circuits in there
and when SPICLK hasn't come for a certain period of time during a
transmission they will abort for the affected data set.

Actually I'm trying to do it any synch communications. SPI, I2C, and
ICSP will be some of the protocols I'll try and implement. Kinda sucks
that there is at time out and since SPI doesn't have an acknowledgement
it makes it even works ;/

I believe the OP (that's you, Jon. ;-) ) has some confusion about what
"synchronous comm" means. Or either I have.

The way I understood it, "sync" means that the receiver provides its
own clock, and it gets sync'ed to the master by some scheme.


Oh, I have no idea. I could be misusing the term then. I do see what you
mean though. I'm not sure though.

What you're talking about, driving something from the parallel port,
is simply clocked. If you have control over the data and clock,
and know how the destination device behaves when it receives them,
then just do it; if your receivers are static, they shouldn't care
about latency, as long as the signals get there in the right order.


Yeah, thats what I thought but since I'm trying to do it in general I do not
know how all devices will behave. I'm just going to assume thats how it
works though so I can get something done and worry about any specific
devices later.

Thanks,
Jon


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