Blacet VC Clock from Synapse

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nateflanigan
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Blacet VC Clock from Synapse

Post by nateflanigan » Tue Apr 06, 2021 6:04 am

Hi, I'm starting to draw out this schematic in Eagle and I can't figure out if pins 2 and 9 of IC 1 are meant to be connected. IC1 is a 4046. Any thoughts?

Page 1

Page 2

4046 Datasheet

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diophantine
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Re: Blacet VC Clock from Synapse

Post by diophantine » Tue Apr 06, 2021 7:38 am

According to the schematic, no. Only crossings with a dot are connected. (Also, looking at the schematic, it wouldn't really make sense to connect them.)

Let us know how you get on with this! Been curious to build John's Synapse circuits!

nateflanigan
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Re: Blacet VC Clock from Synapse

Post by nateflanigan » Tue Apr 06, 2021 3:35 pm

diophantine wrote:
Tue Apr 06, 2021 7:38 am
According to the schematic, no. Only crossings with a dot are connected. (Also, looking at the schematic, it wouldn't really make sense to connect them.)

Let us know how you get on with this! Been curious to build John's Synapse circuits!
Thanks, I thought as much but wanted a 2nd set of eyes. The data sheet shows pins 2 and 9 connected via a resistor which was enough to cast doubt for me.

I'm planning on making the digital pattern generator as well, I'll definitely post about both.

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diophantine
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Re: Blacet VC Clock from Synapse

Post by diophantine » Tue Apr 06, 2021 5:03 pm

nateflanigan wrote:
Tue Apr 06, 2021 3:35 pm
Thanks, I thought as much but wanted a 2nd set of eyes. The data sheet shows pins 2 and 9 connected via a resistor which was enough to cast doubt for me.

I'm planning on making the digital pattern generator as well, I'll definitely post about both.
Yeah, that connection via resistor is just for the PLL configuration. (Makes me want to try that IC out as a PLL...)

Nice - if you do end up getting extra PCBs made, I'd be interested!

nateflanigan
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Re: Blacet VC Clock from Synapse

Post by nateflanigan » Tue Apr 06, 2021 5:40 pm

diophantine wrote:
Tue Apr 06, 2021 5:03 pm
nateflanigan wrote:
Tue Apr 06, 2021 3:35 pm
Thanks, I thought as much but wanted a 2nd set of eyes. The data sheet shows pins 2 and 9 connected via a resistor which was enough to cast doubt for me.

I'm planning on making the digital pattern generator as well, I'll definitely post about both.
Yeah, that connection via resistor is just for the PLL configuration. (Makes me want to try that IC out as a PLL...)

Nice - if you do end up getting extra PCBs made, I'd be interested!
Thanks - I don't really understand how PLL work, I'll likely self etch, but happy to share eagle files.

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drew
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Re: Blacet VC Clock from Synapse

Post by drew » Wed Apr 07, 2021 6:14 am

This circuit looks really interesting.
But can anybody confirm if it works as expected.

It seems to me that the diodes/switches are making an OR gate for the outs of the 4040.
But the diagrams suggest that the 4040 outs are going through an AND gate.

Am I missing something?

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BugBrand
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Re: Blacet VC Clock from Synapse

Post by BugBrand » Wed Apr 07, 2021 2:50 pm

Haven't looked at this for ages (never made it either!) but I agree with drew's observation above - does seem like the ripple counter outputs should be ANDed not ORed.

nateflanigan
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Re: Blacet VC Clock from Synapse

Post by nateflanigan » Fri Apr 09, 2021 8:41 am

Dunno, I’m about finished with a single layer pcb layout. Maybe I should breadboard at least some parts of the circuit before I really dig in.

nateflanigan
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Re: Blacet VC Clock from Synapse

Post by nateflanigan » Fri Apr 09, 2021 9:13 am

Actually looking over this diode OR gate truth table, I think it's doing what it's supposed to.
https://en.wikipedia.org/wiki/Diode_log ... ogic_gates

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