Emax

You made be thinking again.

When I started my experiments I asked for some advice on serial 
communication on a Dutch electronics internet group. One of my 
questions was whether the 4 handshake signals on the standard RS422 
(RTS+, RTS-, CTS+, CTS-) can be compared in some way to the HSKi and 
HSKo signals of the Mac serial port. Specifically I was also asking 
what to do with the + and - signals, given the fact that the 
Emax/Emulator sends a clock signal which is going + and - on the same 
line, while the RS422 expects seperated opposite signals.
I also asked if an independent clock in the PC RS422, running at 
500kbaud would be sufficient, instead of external clocking.  
At the end the experts on this group confirmed that an independent 
clock should be OK, even if it's not clocking exactly at the same 
speed of the Emulator II and that phasing problems can be ignored.
One of the arguments they based their conclusion on was that the 
Emulator II communication protocol is *asynchronous* (as also stated 
in the technical documents of the EII).
Were they wrong ?

And do you know the most appropriate wiring between the 4 
RS422 "clock" pins and the single clock pin of the Emax/Emulator II ?

Or do I understand you completely wrong, and are those "external 
clockable RS422 devices for the PC" not using these 4 signals but 
even another one ?

By the way: what exact link to which RS422 device are you talking 
about ? I reviewed the messages but didn't find a direct link ?

///E-Synthesist

--- In emax@yahoogroups.com, mr julian <jujulilianan@...> wrote:
>
> so the non-USB port didn't work?
> 
> That link I sent the other week was to a 422 adapter card that was 
able 
> to run synchronous.... is the issue that this card can only be 
clock 
> master, or something???
> 
> 
> PS, you do NOT need a digital storage oscilloscope. A logic 
analyser 
> will tell you way more here.
> 
> 
> 
> esynthesist wrote:
> 
> >Thanks Tristan.
> >
> >I'm wondering though: even if we find the actual cause of the 
problem 
> >(timing or signal level), I guess there's not much we can do to 
solve 
> >the problem. Besides making a custom communication board of course.
> >Because I don't think characteristics such as "clock to data 
> >relationship" can be configured on any normal commercial RS422 
port 
> >device for PCs, right ?
> >That's in fact the only reason why I didn't invest in a scope yet: 
> >exactly knowing the problem would be nice, but not being able to 
> >solve it would be frustrating :-)
> >Man ! I would love the standard PC RS422 ports to be externally 
> >clockable ! Why is this (once again) one of those "Mac"-only 
> >features !
> >
> >Question: the RS422 communication "timeout period" on the Emax can 
be 
> >configured with a SYSEX command (from 1 to 127 seconds). But I 
guess 
> >this is not something that can help on the lowel level data 
> >syncronization problem we are dealing with here, right ? I 
> >guess "our" problem is more related to the speed at which a stream 
of 
> >bits (as a whole) is entering the Emax port ?
> >
> >///E-Synthesist 
> >
> >
> >  
> >
> >  
> >
>