XCore Exchange

Ross wrote: Okay, you don't need a clock-multiplier to do that, just two different master clock sources (say two oscillators with a software controlled switch). We just use this multiplier when we want to lock to a external digital stream (the reference given to the clock multiplier from the XCore is derived from the stream).

You will get better performance, lower BOM and use less MIPS (since you wont have to generate this reference to the clock multiplier) if you use fixed master clocks (e.g. oscillators).

Could you show this?

Regarding the thin traces, you show the top layer of the power supply. Power rails have traces that seem to be too thin. Regarding the switching regulators... you are using National's simple switchers (now TI), the ones that need 330 uH inductors... those are huge in size, your board does not have enough space for them. Try to optimize component place to have stable oscillation. National provides a guide on how to do the PCB layout. Look at the following app note (just an example):

http://www.ti.com/lit/an/snva054b/snva054b.pdf

There are higher frequency versions that need smaller inductors (250 kHZ or so).

Maybe not exactly this one, but look at the table Parametrics.
[url]http://www.ti.com/product/LM22678-Q1[url]

You are doing audio... maybe you may want to change to linear regulators, or add some extra filtering to your +/- 12 V rails.

Have fun!

[quote="ale500"]Regarding the thin traces, you show the top layer of the power supply. Power rails have traces that seem to be too thin. Regarding the switching regulators... you are using National's simple switchers (now TI), the ones that need 330 uH inductors... those are huge in size, your board does not have enough space for them. Try to optimize component place to have stable oscillation. National provides a guide on how to do the PCB layout. Look at the following app note (just an example):

There are higher frequency versions that need smaller inductors (250 kHZ or so).

Maybe not exactly this one, but look at the table Parametrics.
http://www.ti.com/product/LM22678-Q1[ur ... uH&FS=True

*Edit: Specifically I think this one:
http://www.mouser.com/ProductDetail/Bou ... OnVNs0s%3d

Several of these would fit, granted some topology layouts need to be fixed and Hardware isn't really my forte, most of my time went into the other boards. Not this one. >.< Exactly why I posted this on here.

And Linear Regulators, Examples. Or if you feel like going the extra mile, wanna help me correct this?

and Traces, too small all over, or just on Pwr Board?

*Edit: I have updated and ran the traces larger on every board. And am working on grinding out a new power supply board. New Edits Up soon.

Release Candidate v2:
-- Re ran power rails on everything
-- Dropped Clock Multiplier - Replaced with two Buffered Crystal Oscillators
-- Upped default trace size as well.

As always, comments appreciated and welcomed. Tell me what I need to check out next. The closer this is to working on paper, the closer it is to showing up in a box on my desk to tinker with.

Not everyone uses EagleCAD.

Bianco wrote:Not everyone uses EagleCAD.

Wow. Quite a blanket statement. Here's one. Not everyone likes apples.

If you had read the previous posts, I'm more than happy to respond to requests. Your post just sounds like well to be honest -- Whining. Do you want pdf or something else. I'm fairly reasonable.

It is almost always better to provide PDFs or PNGs/JPEGS rather than just the source files as they offer lowest barriers to entry in order for folks to participate, and provide feedback. Even though I have Eagle I prefer these other formats for quickly reviewing other's designs as I find it simpler and quicker.

PS the last thing you want to start is CAD war, its only slightly worse than and editor war, before we know it folks will be suggesting that emacs isn't the best editor ;-)

regards
Al

I'm sorry, i didn't want to sound offensive or rude.

Png Renders.

And I think the last thing any of us want is a CAD editor War.

On another note, working on re-doing the Power Board completely.

Going with Linear Regulators and Requiring: Low Noise, Low Ripple, +/- 12V,
+1V, +1.8V, +3.3V, +5V.

Starting voltage I'm considering is +14V [+/- 5%].

Any hints or tips?