[sdiy] 10 step sequencer

[Tim Parkhurst]

Hey Dave,

Just off the top of my head...

I think what you want is something like a sequencer that just makes one
output high, and cycles to the next output on each clock pulse. Right? 

The simplest solution would be to use a 4017 decade counter. This is a chip
that accepts a clock input and makes 1 of 10 outputs high in sequence. You
can limit the count to (for example) 8 steps by tying the 9th output of the
multiplexer to the RESET input. You can keep the output pulse the same width
as the clock input by simply running the output pulse and the clock into an
AND gate (a trick used in the ARP analog sequencer). Unfortunately, this
will require 10 AND gates if you want to the outputs separate. An easier
method might be to run +V and the clock input into an AND gate and run the
output of that gate into the ENABLE input on the counter. I'm pretty sure
that would do the trick, but I'd want to breadboard it before I could
guarantee that. 

You could also use a multiplexer chip (available with 8 or 16 outputs)
driven by a 4 bit binary counter. For each clock pulse to the counter, the
binary count will advance once and select the next output on the
multiplexer. This is the way most analog sequencers work. The advantage of
this is that you can use an analog multiplexer (to switch CVs or other
analog signals), and take advantage of the 8 and 16 output multiplexers
available, and get the counter to count up and/or down (the 4017 only goes
up). I still think the 4017 is the best bet for your application.

If you want, I'll try to look up some specific part numbers. But it sounds
like you need just the basic guts of a sequencer. I don't think you'll have
any problems to get CMOS parts to run on +/-9V. I'm sure other members will
have suggestions too.

Tim Servo


> -----Original Message-----
> From: Dave Krooshof [mailto:synthos at xs4all.nl]
> Sent: Monday, October 13, 2003 5:59 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] 10 step sequencer
> 
> Hi there.
> 
> I'm looking for a sequencing IC for a little pulse AM thingy I'm
> erxperimenting with.
> I'm looking for a [1 input, more outputs] IC that's able to do this:
> 
> On every pulse it gets, it should set this pulse on the next output.
> The pulse it receives, will be 5 to 7 ms wide.
> The pulserate on it's input might be as high as every 10ms.
> The IC should have 8 or 10 outputs, 16 outputs is also OK.
> The pulse on the outputs should rotate over these outputs.
> The pulsewidth should be equal to the clock/trigger pulse (5 to 7ms)
> No more then 1 output at a time may send a logical 1 out.
> Powersupply will be + and - 9 volts from 2 batteries.
> 
> Do you guys (m/f) know of a IC that's able to do this?
> 
> For low power consumption, I prefer a "one stone" sollution.
> I also was thinking of converting a digital counter, but then I worry
> about the pulsewidth, which is kinda important to me.
> 
> Thanks in advance!
> --
> --
> 
> groets,
> 
> _          >^v<        _
> 
> website http://www.dendriet.nl



***************************************************************************
This message is confidential.  The information contained in
this e-mail message is intended only for confidential use of the
recipient(s) named above. If the reader of this message is not the intended
recipient or an agent responsible for delivering it to the intended
recipient, you are hereby notified that you have received this document in
error and that any review, dissemination, distribution, or copying of this
message is strictly prohibited.  If you have received this communication in
error, please notify us immediately by e-mail, and delete the original
message.
***************************************************************************