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[Reply #15 on:]

Not sure what the OP's needs are, but if they need multicore, the Parallax prop has some really nice multi-core ("multi-cog" in Propeller parlance) solutions available.  If you're looking for an AVR-based challenge, carry on

Would be interesting to hear what your needs are for this - there are probably better solutions available.  If your problem requires any kind of serious synchronization, shared memory, etc, FPGAs are probably a better bet (and will blow away anything you can do with the AVR, performance-wise...)

[Reply #16 on:]

All routed, a little cleanup needed, name placements cleaned up...

[Reply #17 on:]

Thanks man!

[Reply #18 on:]

The traces are thin,so its really a problem to etch at home.

[Reply #19 on:]

Jeez Bob, you've got way too much time on your hands

______
Rob

[Reply #20 on:]

@engr_eddy,
I did ask:
"You serious about making this?  I normally design with 10 mil lines so I can snake 2 traces between holes if need and use 0.012" holes for vias. That gonna be a problem for home etching?"
What size can you do?

@Rob,
Actually, this went really quick.  If you're just connecting things by name and not drawing lines all over the page, the schematic goes quick.  Borrowing from the Bobuino design concept meant I had a good architecture in mind when I started.
Being careful with parts placement made most of the routing pretty straightforward. And not having to deal with arcane shield pinouts meant I could arrange the headers to suit the chip's pinout better.

In fact it went so well, I only 4 clearance errors to clean up, and those just needed a slight movement of a corner or a via.

You see the method I use of looping signals back over pins? Eagle's autorouter can't seem to do that, and that lets me get by without a lot of vias as well. Vias take up room, even using 0.012" drill size.

The other thing that helps is making it all thru-hole, lots more room to work with.
Am gonna try dual 644/1284 next.

And when fencing season starts in 2 weeks and I'm coaching several nights a week, I'll have less time.

[Reply #21 on:]

@Engr_Eddy,
Had some time to kill offline waiting for something else, took my laptop.
I fattened up all the lines, beefed up the +5V going around the board, got rid if as many vias as I could for you.
Can you create top & bottom artwork yourself from eagle?
http://www.crossroadsfencing.com/DualATMega328.brd
right-click, save target as, rename to .brd.

[Reply #22 on:]

You've heard of Dueling Banjos?  Well, for one night only!  Right here!  The world famous Dueling Banduinos^®!  Don't miss it folks!  It will be the event of a lifetime!

[Reply #23 on:]

Especially  if you program both as Masters and they try to send commands to each other at the same time

[Reply #24 on:]

And now, for the greatest race (condition) of the century and for your viewing pleasure...

______
Rob

[Reply #25 on:]

Note that not all States yet allow such a partnered processor arrangement. 

It is however cool in CrossRoads home State.

Lefty

[Reply #26 on:]

You think XTAL2 should be left open on one of the parts?

"Full Swing Crystal Oscillator:
Pins XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be
configured for use as an On-chip Oscillator, as shown in Figure 8-2 on page 29. Either a quartz
crystal or a ceramic resonator may be used.
This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is
useful for driving other clock inputs and in noisy environments. The current consumption is
higher than the ”Low Power Crystal Oscillator” on page 28. Note that the Full Swing Crystal
Oscillator will only operate for VCC = 2.7 - 5.5 volts.

The operating mode is selected by the fuses CKSEL3..1 as shown in Table 8-5."

Frequency Range(1)   (MHz)   Recommended Range for          CKSEL3..1
                                                 Capacitors C1 and C2 (pF)
0.4 - 20                                     12 - 22                                          011

Is that what we use?

[Reply #27 on:]

You think XTAL2 should be left open on one of the parts?

I was wondering that as well.  I know a 1 MHz square wave applied to XTAL1 with the default fuse settings brings a processor to life.

Is that what we use?

Yup.

[Reply #28 on:]

How can  I find that solder bridge/pad thing in Eagle? No idea what it is called.
Can add that as an open, be able to close it if needed.
Or add to both chips, then either can be selected as the clock generator.

[Reply #29 on:]

Just make one. I'm no fan of Eagle but it can't take long to make a solder bridge.

______
Rob