Hi adrian, that was a wonderful followup- thanks!!

I was caught by the comment about endstops using 5V logic. But- uhh...They are just going from the pull-ups shorting to ground, so that would work the same on a 3.3V source, I would think. So maybe you can fill me in if I'm missing something from there. Still, I see your point about a number of other chips. but in my experience so many sensors now are *only* available in 3.3v, and I struggle having to run shifters for my 5v arduino projects. The only problem with 3.3v is the potential lack of logic level mosfets. I guess a driver might be needed.

Sure - But not all endstops are purely mechanical though. Many use Optical triggers (IR Gates etc) or Hall Effect Sensors, some even have used Capacitance sensors... So what you said above is totally correct if you are just referring to mechnical NO/NC micro-switches... But starts to fall apart if you have say a 5v or 12v IR Gate or HallEffect switch - This is why lots of printer boards offer both 5V rails or 12V rails on the limit switches.  Limit switches tend to come into view from an Industrial standpoint - where 5, 12 and 24v signalling is the norm due to the cable runs normally seen which makes 3.3v largely more difficult to work with...

And yes the ChipKit's are outwardly nice.. but being PIC based, there is some inherent differences when you get into the timing phases of a things done in native PIC which makes it all a bit messy if you aren't working within those confines to begin with.. suffice to say its just easier to skip past this and work with an ARM

I was caught by the comment about endstops using 5V logic. But- uhh...They are just going from the pull-ups shorting to ground, so that would work the same on a 3.3V source, I would think. So maybe you can fill me in if I'm missing something from there. Still, I see your point about a number of other chips. but in my experience so many sensors now are *only* available in 3.3v, and I struggle having to run shifters for my 5v arduino projects. The only problem with 3.3v is the potential lack of logic level mosfets. I guess a driver might be needed.

There's another board (mega form factor) that I think was fairly underrated. It seems to have gone under everyone's radar last november.  The chipkit32 http://www.digilentinc.com/Products/Det … PKIT-MAX32
I got to meet the dude who convinced digilent to make them, and a few interns who spent all last summer (2012) porting a ton of libraries.  I remember them telling me that they have a row of headers that are 5V tolerant in an effort to make it truly arduino compatible (by using a resistor divider.) 

But overall, I think merely because of Paul's godliness, the Teensy 3.0 would be better. Certainly a PCB board that pins the 3.0 to be similar to the mega shouldn't be impossible, though I guess it has to few pins to cover everything.

I didn't realize teensy 3.0 can fully emulate the atmega. That's awesome!! Thanks for the heads up. I really need to get over the miniscule barrier of doing a project with one of them (barrier greater than the atmega328 because of having run with the atmega328 a lot already.)

Needs lasers. Lot's of lasers.

You had me at the lasers!

I can't honestly say that I understood everything I just read, but I'm in!

Now I just have to figure out where to start...

I wonder how much of the 3d printing code would be immediately adaptable to the TEENSY3.0. I'm assuming the teensyolu came about from the teensy2.0++ arduino variant.

Using the ATMega emulated core, all of it. Natively - at the moment - not much of it. So you get a slight benefit given the higher performance of the emulated core versus the actual core, but full exploitation of the 32-bit environment is lost.

The other issue is, the ARMs have horrific protection capabilities compared to the fairly robust ATMega range... you can be quite abusive to an ATmega or variant and it will cope - but the ARMs tend to go pop if you look at them sideways wrong, particularly when it comes to I/O levels... which leads me to:

Most of the current sensors/limit switches/external peripherals for 3D Printing is based around a 5V TTL line level signalling, where as the ARM processors use a 3.3V CMOS line level signalling.. meaning all the signalling from End-Stops needs to be run through a logic-level converter as a minimum.. because a TTL signal into an ARM pin will kill it fairly instantly.. 

So its possible, and I will be working on a variant that trys to exploit the Arduino DUE a bit more (since its a platform that we can just plug a RAMPS shield onto - once the logic-levels are dealt with...) , but there is a bunch of 'reliability issues' I feel will be introduced as a result of the 'less robust' nature of ARMs in users hands when dealing with I/O along with the increased speed of the processor means existing timing loops will be a bit screwy (its not all 'clean' in Marlin unfortunately...)...

But, the clock speed isn't the main issue so much.. well it is, but its influence isn't as dramatic as you'd think.... Despite the 16MHz clock speed, the actual "Movement Planner" of Marlin runs at around a paltry 10KHz.. yup.. Killohertz ... This is for a bunch of reasons.. and yes even if we only got a 4x improvement, 40KHz is a lot better than 10KHz, but its not going to be a massive noticeable improvement in *performance* - since the limiting factors on speed is more to do with axis and inertia and traditional mechanical issues rather than a case of motherboards running out of puff... Obviously we could do things like increase the recevie buffer.. but @ 12mb/s, there isn't really a bottle neck on anything that uses USB comms (outside of virtual-serial drivers that is!)...  So yes - more MHz is always nice - but its not actually a limiting factor these days on a Solidoodle or the like.

That is a bit more of an expanded follow up for you Tomek... hope that sheds some light on it Feel free to fire away with any other thoughts/comments or if you want some more clarification!

Cheers for reading the first post before clicking 'reply' Yes, as is explained in the First Post:

Therefore, its more rather the new SD motherboard AND Spuds look just like a Printrboard... Also as stated in the first post - there is a key difference - Spuds unlike the Solidoodle board OR the Printrboard does NOT have onboard stepper drivers - for the reasons elaborated and demonstrated in this thread by Lawsy

So yeah - maybe re-read the first post then I can happily clarify any remaining questions? I think my first post presents all the information you could possibly want, in a far more exhaustive manner than Solidoodle have so far with their re-work of a printrboard

The teensy3.0 is kinda like the arduino duo in terms of being a 32bit arm processor, but has been around longer and has a great one man developer-master who has adapted the IDE to make a lot of things directly usable on the TEENSY platform.

It seems like pretty soon we could use a faster motherboard, or at least simply run the processor at its still-spec 20mhz. I'm kinda surprised people are still running everything at 16mhz (most code has become much more adaptable to differences in processor speed than it was back in ye old arduino0.22 days)

And if it's really the computer to arduino connection that is making the speed limit...why can't I bump up the baud rate to something higher?  Edit: Well, if this ever was the problem, I see you do have the solution!

Sorry for dumping those confusions on you, Adrian. I think Spuds is great, and I applaud the movements towards consolidating some good ideas and improvements into a new board.

The fact that Solidoodle have switched to the printrboard is hugely concerning.

Fortunately Adrian has solved this issue in his design.

You can put me on the list to buy one - as long as the shipping from "down there" to "up here" doesn't run the cost of another machine

And at this stage, not sure what I'll have to possibly send out with the first test batch - will wait till I get the boards back and know they work and then figure it out ... but yeah, will be keen for a few people to have a play in real life

Ahem, so how many of your first batch of PCBs are spoken for?