[sdiy] 4514 w/4516

[Tom Arnold]

On Sat, Jan 15, 2005 at 01:05:47PM -0800, Tom Arnold wrote:
> I figured expanding this 16step sequencer board to 32 steps was going to be
> as easy as chaining a second 4516 off the first 4516, but then my brain
> finally kicked in yesterday and I realised that by chaining them they'll
> count up to 8 bits as a pair unstead of one counting up 4 bits and then the
> second counting up 4 bits.

So, I'm replying to myself again.

First with a rant.  Frys sucks.  I mean, this isnt a huge surprise to anyone
but the real surprise is that they can indeed continue to get worse.  Its
bad enough that they only carry NTE parts, whats worse is the aisle is
slowly shrinking as they sell out of what they have.  I should offer them
$100 for the entire aisle and see if they take it.

Anyway...  If you use a 4516 to slave from another, there is a small but
noticable delay when it carries the bit.  The delay depends on the width of
your clock pulse also which makes it more fun to deal with.  Survey says?
4514 aint good for this application.  I could work around the delay with
some logic and in fact I started to, then I realise that much more quickly I
could code up the previous mentioned scenix chip to act as a pair of 4514's
and fairly cleanly wedge it into the existing circuit.  So thats what I've
done still feeding a pair of 4514's.  Still some kinks to work out, but I'll
nail them after some sleep...

It just feels like overkill to use a microcontroller for this, on the other
hand it will save close to half a dozen bits of logic and associated wiring
and board space, so I guess its a win in the end...

-- 
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 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
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