Re: [sdiy] microcontroller MIDI sequencer

[Roman]

Hi,
I'm actually making something similar. In fact, this morning I got 
PCBs for it from PCB fab. Mine is 16-step with only 2 parameters 
(note/velocity), but can be configured other ways too.
As I see, you need 33A/D inputs to achieve your goal. So make part 
of existing 32 inputs multiplexed. Add 4052 or something like that, 
and use 1 I/O pin to toggle 4 inputs between 8 pots. Now you can 
have your additional 8 octave pots, tempo pot and 3 others for 
whatever purpose.

As for pots with 12 detents - Bourns makes 10-detents cheap 
slimline conductive-plastic pot's, so maybe you could search there 
for 12-detent version. Or use rotary switch.

I'm not sure what you mean by MIDI I/O pins. Velocity and note is 
not pin-oriented, it's a message on serial bus, so could you 
elaborate more what do you mean by that?
But if you mean bits, go there:
http://www.borg.com/~jglatt/tech/midispec.htm

Roman

---- Wiadomość Oryginalna ----
Od: Blitzcraig <blitz at nmt.edu>
Do: synth-diy at dropmix.xs4all.nl
Data: Wed, 19 Mar 2003 15:42:24 -0700 (MST)
Temat: [sdiy] microcontroller MIDI sequencer

>
>My new project is to create an 8 channel MIDI sequencer using a 
Motorolla
>HC12 microcontroller.
>
>The design is very basic...
>pushbutton toggle (start/stop sequence)
>tempo pot with numberic display
>
>8 channels consisting of...
>pushbutton toggle with LEDs (on/off)
>gate time pot
>velocity pot
>note value pot
>
>I have most of the code written, the HC12 has an onboard A/D (32 
channels
>total).  I would like to have an octave pot for each channel, but 
this
>would put me over the number of A/D channels available.  
suggestions?
>
>I'm looking for a notched potentiometer for the note values (12 
notches),
>suggestions?
>
>I can't find a resource for standard MIDI pin I/O (such as which 
pin is
>note number, velocity, etc.), suggestions?
>
>Any other suggestions would help.
>
>-Joe Craig
>www.blitzcraig.com
>
>
>