[sdiy] DIY PG-800?

[Luís Marka]

Also got curious about the possibility of building a PG800 for my JX8P, 
and I could find the difficult parts (the uPD7001C and the uPD8048HC) at 
utsource.net: $10.00 each. Not that bad!
So if you guys get to read the firmware from a PG800 I am very likely to 
build one for myself!

Luis Marka



Matthew Smith wrote:
> Quoth Colin f at 2008-12-24 11:07...
>> http://www.colinfraser.com/jx10/moreinfo.htm
>
> Quoth Ullrich Peter at 2008-12-25 00:20...
> > And you can have a look at the Service Manual of the PG-800 that is
> > part of the JX8P Servoice Manual -
> > at least the schematics of the PG-800 are here. It works with an 8048
> > microcontroller that can normally be copied
> > as it had no code protection as far as I know. You should fine someone
> > that has the PG-800 and can copy the 8048 for you...
> ...
> > maybe some information also in the MKS70 Service Manual:
>
> Thanks guys!
>
> Colin's page provides all the codes bar the one for the 'write' command.
>
> Looking through the PG800 and MKS70 service notes reveals the wiring 
> of the connector.
>
> Certainly a copy of the firmware would make it possible to reproduce 
> the original circuit. (I'm not sure if uPD7001C ADCs are still 
> manufactured but everything else is standard parts, much to my 
> surprise.)  This, however, still means that access to a PG800 would be 
> required.
>
> To complete the picture so that the system could be reproduced without 
> the firmware I would need to know details of the serial protocol that 
> are not documented in the service notes:
>
> * Should data be presented on the rising or falling edge of the clock?
> * Is the data 7 or 8 bit?
> * What polarity is the data (is the logic inverted?)
> * What part does the 'ready out' line play?
>
> ...questions that could (possibly) be answered with a PG800 and a 
> scope.  (Have scope, not PG800 - back to that again.  Doh!)
>
> Maybe it would just be simpler to use sysex, even if it does mean that 
> I'd have to implement MIDI merge :-/
>
> /me goes hunting for MIDI merge algorithms.
>
> Cheers
>
> M
>
>
>