Emax

Hi E-Synthesist,

Yes, I was lucky to find that document. It came with the latest Emax
II rack I bought :)

Good to hear the RS-422 interface is moving ahead.

/Tristan

Monday, September 14, 2009, 3:21:43 AM, you wrote:

e>   
e> Thanks for sharing the Emax-2 MIDI and RS422 specs !
e> This kind of documents is so hard to find.
e> I've downloaded it right away  

e> Regarding your question about progress on the RS422 device:
e> there has been a lot of silence indeed, but I hope to receive a
e> test device very soon in my postal mail box. This particular device
e> seems to have run my test program successfully, so I hope I can
e> even make it actually load/unload banks between a PC and the Emax (and even EII !!)

e> ///E-Synthesist
e> --- In emax@yahoogroups.com, Tristan <tu@...> wrote:
>>
>> Has there been any progress with the USB to synchronous RS-422
>> interface?
>> 
>> My work on the synchronous RS-422 to asynchronous RS-422 converter ran
>> aground when I found the microcontroller was unable to handle the
>> number of interrupts generated by bidirectional communication at 500k
>> baud. The interface also needs to handle the baud rate switching on
>> the Emax side itself by either monitoring the transfer protocol or by
>> receiving some non-Emax sysex messages from the PC host.
>> 
>> The potential issues with either of these options mean extensive
>> debugging and ongoing upgrades to firmware would probably be required.
>> However, I believe it would be possible for the host PC side to use an
>> RS-232 port with auto baud rate setting, so it could potentially work
>> with any USB to RS-232 or built in RS-232 interface. Anyway, to move
>> forward I will need to upgrade to a faster microcontroller which will
>> also allow for in circuit flash upgrade of firmware. But if the USB
>> alternative is already working then there may not be too much point.
>> 
>> I found a copy of the Emax 2 MIDI and RS-422 specifications which I
>> have scanned and uploaded to the files section. It details the 12 bit
>> and 16 bit high speed sample transfer protocols as well as the Emax
>> bank image transfer protocol. It appears the Emax 2 was designed to be
>> compatible with the RS-422 CDROM drive after all! It also explains
>> differences between the implementations on the Emax and Emax 2 as well
>> as some Emax 2 bugs and corrections in various OS revisions. I also
>> have hardware information on the Macintosh serial interface that the
>> Emax is designed to interface with, but I have not uploaded it yet.
>> 
>> /Tristan
>>