[sdiy] PCB digital signal layout question

[ASSI]

On Friday 02 August 2013, 10:50:03, grant at musictechnologiesgroup.com wrote:
> I'm removing the original EPROM and using a ribbon cable to relocate it
> onto my memory expansion board.

Use the IDC-DIP connector like the Miniwave for the place of the original 
EPROM.

> For those lines mentioned, I can just run traces from
> one chip to the next in pretty row -or- I can actually pull then to nice
> fat bus lines running elsewhere on the PCB I'm making. Do you think
> there is a preference?

Just weave them through in a (mostly) parallel fashion.

> If just run them in pretty rows-chip-to-chip it's OK, but I don't have
> as nice an option of putting a bypass cap there.

Are you trying to make that PCB single-sided?

> If I take the original
> signals and run them up to bus lines outside the land pattern of the
> EPROMs, the I can add the bypass caps -or- really I could do both, but I
> suppose that would add small ground loops. Just wondering if anyone has
> done this before?

Straight & parallel routing is preferrable IMHO.  If you're worried about 
ground loops and EMI, spend two more (inner) layers and put a proper supply 
plane for VDD and GND there.  Depending on how fast the signals are and how 
long the bus gets (including the length on the original PCB) you may also 
need to add termination.


Regards,
Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Waldorf MIDI Implementation & additional documentation:
http://Synth.Stromeko.net/Downloads.html#WaldorfDocs