PCB layout precautions - digital clock, sequencer, dsp

[teej212]

Im working on a pcb for a tap tempo clock controlled sequencer that in turn controls one of the pot inputs on a spin chip.  Im also including input and output buffers on the same board.  What special precautions do I need to take to prevent ticking, noise, etc? ive never worked with the 4017 chip or the electric druid tap tempo chip and have a feeling that they could be quite the noise makers with the fv-1 circuitry.  thanks!

p.s. - no LDR is involved, using the CV output of the sequencer (votage divider used to bring the output to about 3.0-3.1 v) to control one of the pots on the spin chip.

[teej212]

separate ground planes for audio and digital sections? or if I have enough distance between them will I be ok? how would you recommend sorting out the power supply? separate for the tap tempo/ sequencer chip? throw me a bone! would love some help!

[slacker]

I'd do pretty much what you've already suggested, keep the grounds separate just joined at one place, probably at the DC negative input. Keep the digital lines as far away from the audio parts of the circuit as possible.
I don't know what voltage you're going to run the taplfo and cd4017 at, they should work on 3.3 Volts the same as the FV-1 so they  could share the same regulator but for the cost of the extra parts I'd use a separate one. You could set your layout up so you can use just one regulator and leave the second one unpopulated unless you find you need it. 

[teej212]

I was planning on running the tap tempo and 4017 at 5 v, then regulating the 5v down to 3.3v for the spin. would it be better to regulate the 9v down to 5v and 3.3v simultaneously in order to keep them separate?

i'd love to pick your brain slacker, you really kicked off my interest in the spin chip - you and ice 9 know your stuff!