Patchable Programmable Modular pt2

Clive Jones CJones at sni.co.uk
Fri Feb 23 20:39:00 CET 1996


Hi Chaps

Thanks for all the replies - I came this morning and my mail box was full   
to the brim! I was a bit hard on Stefan yesterday - sorry, I had a bad   
afternoon that communicated to my post (I know. I know). Here's a bit   
more info on how my design would take shape. The modules would be 5-bit   
binary coded - *hardwired* not using DIP switches (not required -   
additional expense). These are just read by the uP to determine the   
system "configuration" - plug in anywhere, the uP reads the backplane and   
builds an "image" of the system set-up. Module numbers would have been   
something like;

Dual VCO - ID# - 01
Dual LFO - ID# - 02
Dual 12/24db LP filter with adjustable "spider" resonance (tm) - ID# - 03   

Lag processor ID# - 04 (I bet you can't guess were I nicked that design   
from!?)
etcetera

5 bits gives a max of 32 different modules - enough for a discerning   
modular enthusiast! Interface. Each module would be limited in it's own   
hardware interface - 16 switches, 16 LED's, 16 potentiometers, 16 jack   
sockets. Limiting the hardware for each would mean that the same   
*precise* amount of memory could be reserved for each module - only   
expansion limit is the amount of memory installed, which, could be   
overcome anyway by paging RAM. Switch debounce is software controlled.   
All of these functions could be programmed using a single 8255A   
peripheral interface (IC) per module. A standalone pot scan feeds the pot   
settings through 4051's into the 8255A and the system uP reads the   
results on one the the 8 bit I/O ports of the chip - simple as ABC.

Something I didn't state very well yesterday regarded patch recall. The   
uP would indeed remember the patch connections (which was the basis of   
the design)  and display how to make to necessary re-connections on patch   
recall, *but*, the uP would have to digitize the CV's/Gate voltages *as   
well* otherwise your just recalling the patch connections, which, when   
plugged in would produce a sound that reflected the current module front   
panel settings. This of course is what most of us know as the "manual"   
setting.

All in all - I though it was a very constructive post, lots of references   
to ARP and EMS patch matrix's and graphical patch representations using   
screens, vacuum flourescent displays, and LED's.

Okay so who's gonna' make it then?

Btw, would all those West Coast chaps save me a bit of blue sky - it's   
done nothing but snow here for the last two weeks off and on (Windsor   
Castle looks nice though).

Clive

//////////////////////
/<c.jones at sni.co.uk> / ...and on the 8th day
/01344 850213 Work   / God made Synthesizers
/01344 850209/291 Fax/ ...and God was called
/01628 602106 Home   /   ' Tom Oberheim '
//////////////////////






   




More information about the Synth-diy mailing list