Emax

Sounds great that standard USB serial comms is being used.

I don't know about the clocking part of your hardware experiment, but 
from a signal perspective I was thinking that RS232 can be used too, 
as long as you can clock at 31.25 internally and clock externally for 
the 500kbaud. The Emulator II document states explicitly that its 
port is both RS422 and RS232 compliant (using the EII TXD-/RXD- only 
towards the RS232 TXD/RXD pins), but that the 500kbaud speed must be 
supported in both cases and that "this is typically not supported by 
RS232 chips". I guess the same principle holds for the Emax ?

To answer your question about the 31.25kbaud speed: with my USB<--
>RS422 adapter it is possible to clock internally at ANY speed 
between 200 bps and about 1 Mbps; the chipset seems not to use the 
standard "divider" approach, but another "new" thing in a "new" IC :-
) So I could clock at 31.25 and 500 kbaud simply by instructing the 
port to do so.

///E-Synthesist

--- In emax@yahoogroups.com, mr julian <jujulilianan@...> wrote:
>
> 
> 
> esynthesist wrote:
> 
> >If some of you succeed in creating hardware for the RS422 it would 
be 
> >great that this library can be used. If some special hardware 
> >specific library must be used I can get in trouble with freeware 
> >licensing for EMXP... unless that library would be completely free 
> >also.
> >  
> >
> it's just using a standard windows USB serial port driver so far. 
in 
> this case, you'll see it just as a normal USB serial port... if it 
needs 
> something more than that, I could be slowed down a lot, as I have 
no 
> windows driver experience.... will have to look more into it if 
need arises.
> :-)
> 
> anyway - I ordered RS422 chips yesterday. should have them in a few 
> days, I hope. then will experiment with the emax, and see what i 
can see.
> 
> >PS: the fact that the host must initiate the communication at 
31.25 
> >kbaud and then has to switch to 500kbaud is something to think 
about 
> >when using external clocking.
> >
> hmmm... of course standard RS232 ports don't do 31.25 or 
synchronous.....
> possibly the simplest thing to do is to tell the serial interface 
to run 
> at 19.2k, and i can make that value actually set the interface to 
31.25 
> similarly, tell the interface to run at 115k, and I can make it run 
as a 
> synchronous slave. I don't think that will cause problems in the 
driver 
> side.
> 
> speaking of 31.25 - how did you select that? was it one of the 
standard 
> baud options with your RS422 ports?
> 
> > I suppose and hope that even this 31.25 
> >kbaud is clocked by the Emax to the Mac, so that the host doesn't 
> >have to change from internal clocking to external clocking all the 
> >time.
> >  
> >
> naah... it probably does change.
> but that's OK.
> very simple to do on the AVR side. just need to change a bit in a 
> register, and flush serial port buffers.....
> :-)
>