[sdiy] analogDNA

[Ingo Debus]

Am 17.06.2006 um 23:19 schrieb Rob:

> I am designing a programmable analog modular synthesizer. Each  
> analog module
> has a digital PCB to store/recall pot and switch settings (as local
> patches), along with a small 16x2 LCD. I am using PIC18F4680's and any
> analog synthesizer design can be "digitised" using DAC CV's,  
> digital pots
> and software switches.
>
> A Global patch facility is also supported, whereby all modules are
> programmed from a central Patch module linked to the outside world  
> via MIDI
> and with unlimited patch storage via a memory card. I plan to use  
> CAN Bus
> technology to pass Patch data to/from the central Patch module to  
> individual
> modules. Data transmissions are therefore relatively small (32  
> bytes) and
> infrequent.

Why not use MIDI also for connecting the analog modules to the patch  
module?
For debugging an analog module could be hooked directly to a computer.
In the simplest case the "patch module" could be completely passive:  
the global MIDI input is just routed to all analog modules; and the  
outputs of the analog modules are just ORed. This is possible if the  
modules only send something on request. If the MIDI outputs of the  
modules are open collector, it could simply be a wired-OR.
Of course in that simple case there's no patch storage capability in  
the "patch module". But perhaps the processors in the analog modules  
could do that job too. Still no memory card interface though.

But why bother with a different protocol (CAN, I2C) if you're going  
to use MIDI for communication with the outside world anyway?

Ingo