sequencer / arpeggiator / echo

The Old Crow oldcrow at oldcrows.net
Thu Nov 18 07:07:35 CET 1999


On Wed, 17 Nov 1999, Byron G. Jacquot wrote:

> >   Well if you want midi, then you're probably looking at a 
> >micro based sequencer, even for 16 steps..
> 
> What he said.  By the time you've gone through the hassle of setting up even
> a simple logic circuit for doing MIDI parsing or generation (say, with
> 4000/7400 series gates and some kind of UART), a microprocessor will have
> long since proven it's usefulness.

  I used Z8 MCus for years to do MIDI projects, but more and more I find
Microchip PICs to be faster and cheaper.  For simple things like a MIDI
filter or channelizer, one PIC chip and the parts for MIDI in and out are
pretty much all that's needed.  A pretty good sequencer would benefit from
a microcontroller that can address external RAM, however.  I fit something
like 37 minutes of realtime (quantized to 64th note intervals) MIDI data
into the ~56K open RAM area of my old CP/M machine, provided that gobs of
controller data didn't fill up the buffer.  These days, I would just add
more RAM and a memory bank selector circuit.  (Actually, I *did* do this
to the CP/M machine in 1984--192K of DRAM available in 3 banks with a 16K
common block shared between all banks.  Used it as a RAMdisk).

  --Crow

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