AW: Re: Analog Sequencer Poll

[brad sanders]

>> I have in front of me here an ARP Sequencer manual. On the ARP sequencers,
>> they have this funky random mode, where it picks out which notes to play 
>at  random... how would ya implement this ? (without using a CPU!!!). 

>You don't need CPUs for everything (;->) (;->)

As a newcomer to this list, I've been following this discussion with
some interest. I can't resist asking any longer: is there any
*particular* aversion to the use of micros amongst the members of this
list? I mean, after all: a micro can do all a 4017 does - it's just a
matter of "coding" in silicon vs. coding in solder.

I ask this because this seems to me the PERFECT place for a micro of
the 20 pin, low power variety. Attach it to a pair (or more) of analog
MUX's, and you got a very flexible sequencer. In fact, I did just this
to build a programmable waveform generator. It has eight steps/wave, a
programmable output filter (just for waveshape smoothing) and TWO
outputs, with tightly controlled (adjjustable) phase between the two.

In such a simple app, there's nothing really "scary" or "difficult"
about a micro. You just treat it like any other 20 pin logic device:
when it don't work, throw it out and pop in a new one (not for
debugging of course - but after the code is done). 

Alternatively, has anyone considered using a 74AHC283 instead of a
counter? This is a four bit ALU and "accumulator" on a chip. By
controlling the four data input lines and the five ALU control lines
(three for op sel, carry in, carry out, etc) you can pretty easily get
"random" steps, or "skips" or go up or down or....

Just a thought...

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