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Multiplexing chips

Multiplexing chips

2006-12-15 by Andrew Scheidler

Looking at the Sequential Switch info, am I correct in understanding how
the 4051 chip operates:

There are three inputs, together representing a 3 bit number. When
voltage is applied at an input, that turns that "bit" on. So by way of
those three inputs, you can address one of the 8 outputs of the chip.

If you were to have three ON/OFF switches feeding those 3 inputs, you
could use the switches to choose which step of the SS was active. (ie
switch 1 & 3 on and 2 off would activate step #5... etc)

Am I understanding this correctly?

If so, there certainly must be a similar chip that has *4* inputs and
can address 16 steps... can someone point me towards this, or at least
give me a clue to where I should start looking?


I am looking for a way to build a 16 step sequencer that is addressable
per step via 4 on/off voltage inputs.


Andrew

Re: Multiplexing chips

2006-12-15 by John Mahoney

At 01:57 PM 12/15/2006, Andrew Scheidler wrote:
Show quoted textHide quoted text
>...
>If so, there certainly must be a similar chip that has *4* inputs and
>can address 16 steps... can someone point me towards this, or at least
>give me a clue to where I should start looking?
>
>
>I am looking for a way to build a 16 step sequencer that is addressable
>per step via 4 on/off voltage inputs.
>
>Andrew

Well, the CD4514 or CD4515 might serve your needs, but they are not
switches; they are decoders which output normally high or low logic
signals. They can be used to control switches, etc.

Used way back when by Thomas Henry in his SuperSeque in Polyphony
mag. He used the CD4516 as a counter.

These parts are in production:
http://focus.ti.com/docs/prod/folders/print/cd4514b.html
http://focus.ti.com/docs/prod/folders/print/cd4516b.html
--
john

Re: Multiplexing chips

2006-12-15 by hitchindave

The CD4067, and others (e.g. HEF4067) is pretty much a 16 channel version of the 4051. Alternatively you might be able to use 2 4051s with the MSB switching the INHIBIT on/off. Probably be way fiddlier this way though, needing extra logic. Haven't tried this yet, but have been looking at my CGS28 sequential switch and wondering.......

4067s are more expensive than 4051s, but curiously, quite cheap from RS in the UK if buying in tubes of (I think) 15.

cheers,

Dave
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "Andrew Scheidler" <xpandrew@...> wrote:
>
> Looking at the Sequential Switch info, am I correct in understanding how
> the 4051 chip operates:
>
> There are three inputs, together representing a 3 bit number. When
> voltage is applied at an input, that turns that "bit" on. So by way of
> those three inputs, you can address one of the 8 outputs of the chip.
>
> If you were to have three ON/OFF switches feeding those 3 inputs, you
> could use the switches to choose which step of the SS was active. (ie
> switch 1 & 3 on and 2 off would activate step #5... etc)
>
> Am I understanding this correctly?
>
> If so, there certainly must be a similar chip that has *4* inputs and
> can address 16 steps... can someone point me towards this, or at least
> give me a clue to where I should start looking?
>
>
> I am looking for a way to build a 16 step sequencer that is addressable
> per step via 4 on/off voltage inputs.
>
>
> Andrew
>

Re: Multiplexing chips

2006-12-15 by hitchindave

The CD4067, and others (e.g. HEF4067) is pretty much a 16 channel version of the 4051. Alternatively you might be able to use 2 4051s with the MSB switching the INHIBIT on/off. Probably be way fiddlier this way though, needing extra logic. Haven't tried this yet, but have been looking at my CGS28 sequential switch and wondering.......

4067s are more expensive than 4051s, but curiously, quite cheap from RS in the UK if buying in tubes of (I think) 15.

cheers,

Dave
Show quoted textHide quoted text
--- In cgs_synth@yahoogroups.com, "Andrew Scheidler" <xpandrew@...> wrote:
>
> Looking at the Sequential Switch info, am I correct in understanding how
> the 4051 chip operates:
>
> There are three inputs, together representing a 3 bit number. When
> voltage is applied at an input, that turns that "bit" on. So by way of
> those three inputs, you can address one of the 8 outputs of the chip.
>
> If you were to have three ON/OFF switches feeding those 3 inputs, you
> could use the switches to choose which step of the SS was active. (ie
> switch 1 & 3 on and 2 off would activate step #5... etc)
>
> Am I understanding this correctly?
>
> If so, there certainly must be a similar chip that has *4* inputs and
> can address 16 steps... can someone point me towards this, or at least
> give me a clue to where I should start looking?
>
>
> I am looking for a way to build a 16 step sequencer that is addressable
> per step via 4 on/off voltage inputs.
>
>
> Andrew
>

Re: Multiplexing chips

2006-12-15 by sasami@hotkey.net.au

>Looking at the Sequential Switch info, am I correct in understanding how
>the 4051 chip operates:
>
>Am I understanding this correctly?

Yes, though as with all CMOS, you would need to have a (100k) pull-down
resistor from each address input to earth to supply the "0" value for when
the switch is off. Also put a 1k resistor between the address input and the
switch to provide protection for the chip.

>If so, there certainly must be a similar chip that has *4* inputs and
>can address 16 steps... can someone point me towards this, or at least
>give me a clue to where I should start looking?

It is the 4067.
You can also use two 4051 with their inhibit inputs being used to select
which chip is on at any given time.

Ken
_______________________________________________________________________
Ken Stone sasami@...
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