up down counter

[ian-s]

Hi Howard

Great job on the forum BTW

Would like to post this reversible sequencer patch which does the same thing Rob's does except it uses Flip Flops and gates to create a synchronous binary up/down counter. Robs is far superior in terms of module count and cpu%. The only thing my approach has is the ability to fool with the bit order, lots of flashing LED's and the irony of using a digital emulation of an analogue circuit to emulate a digital circuit.

The basic ripple UP counter is easy, just four JK (that's not what Clavia call them BTW) flip flops in series. To make it count DOWN, use the complimentary outputs of the flip flops to clock the next stage. The UP/DOWN signal just selects between the two Flip Flop outputs. It must be synchronised to the clock (orange coloured gates) otherwise the more significant bits change (in an interesting way) when the direction signal changes state.

The last set of D type Flip Flops makes the outputs change in sync with the clock. If omitted, the ripple delay between each stage produces glitches in the control voltage making the sequencer behave strangely.

Although probably ultimately pointless, I did (re) learn a lot about basic digital circuits, which may come in useful.

[ian-s]

looks like I have learned something else, save and reload to make sure it still works before posting.

On my system, after loading the bit2 and bit3 flipflops go at the same rate as apposed to bit3 being half the frequency of bit2. This means that it does not work as I intended. If I drag a momentary switch into the patch and change the clock source from the clockgen 1/16 out to the switch out, I can advance manually no problem. Even stranger, if I then reconnect the clock cables to the 1/16 output, it works properly.

[mosc]

g2ian.

First, welcome. It's great to have you here. There are lots of folks interested in electronic music on this site, not just those interested in the NM.

Your patch is a thing of beauty. Let me tell you, I tried setting up a binary up/down counter myself and I couldn't get it to work. It's much easier to design digital logic with a conventional circuit diagram than with patch modules and patch cords. I take my hat off to you.

I think this is the best way to go, if the Clavia people added the up/down feature to the counter it would be a piece of cake. Rob's method has a lot of complexity with the limit detectors. One thing he did add is some kind of S/H circuit to make it possible for the notes to retrigger.

I've been playing your patch for several minutes. There are come interesting glitches that happen irregularly. I like to use an audio rate oscillator to set the fwd/rev. In the analog days, the frequency drift added the necessary uncertainty. With this stuff, you get repeating patterns unless you do something to add uncertainty.

I've never use the phase mod, pretty interesting in itself.

Lots of fun.