new question form a noob :)

[vulcan2000]

so ive been doing a little more research but i cant seam to find an answer to this question. in anticipation of getting my digix for my project a question started rattling around in my head.
  i know that 3.3v shields should stay with 3.3 and 5 with 5 etc... and as far as i can tell sticking with that in mind you can stack as many as you have processing power and memory for library's for... however, mine is going for a special large build 3d printer set up. so it will be dedicated to the main board only. with one exception.
 i REALLY want a color lcd touch screen to go along with this. but here's the issue. this one is specifically designed to only use the pins at the end and the spi plug and it doesn't cover the rest of the other pins. it meant for a DUE/mega they make it both in 5v and 3.3 but the shield, mini shield what ever you want to call it have no female pin sockets on the other side of it.  with out those i cant plug in the control board form the printer.  here is the question. does a color lcd require dedicated instruction signal that prevents it form have anything stacked with it? ie.. if i desolder the current pins and solder standard stackable pins will it work to then plug the controller shield on top of it.
ill post a pic when i get home of the lcd and shield.

[vulcan2000]

rather than just a pic heres a link to the exact item http://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=148_211&products_id=2237
 
and the 3d printer control motherboard/ breakoutboard
http://robosavvy.com/forum/viewtopic.php?t=6801
and an ebay page that describes the mobo v2.4 better
http://www.ebay.com/itm/MakerBot-RepRap-Motherboard-v2-4-/280824693815#ht_7673wt_1040

[digistump]

SPI pins and I2C pins can be shared between devices (shields, etc) - they are shared buses. SPI devices require on select line per device that can not be shared.


All other pins can almost never be shared - if a shield uses that pin (doesn't just plug into it but uses it) then something else can't use it as well.


Both things you link to use SPI - they can share that - but they also both use the D22-53 pins and I imagine they use many of the same - that won't work.

[vulcan2000]

thanks for the info. that's to bad but ill come up with something. 

[vulcan2000]

i think form the info you just gave me and more reading on the available idc header on that main board this is what im looking for http://www.ladyada.net/products/tfttouchbreakout/

[digistump]

YOu might be able to make that work by using the pins the mobo doesn't use - but you'll have to tweak the library to use those pins

[vulcan2000]

cool... if i can get all the hardware to be compatible then its just a matter of learning the software enough to tweak it to make everything work.
 
side question. since you've looked at the board im going to be using for my project(granted no datasheet etc...)... let me bounce this off ya. its intended for a mega 2650.  the designer insists that i need a mega... however, and again obviously this shows how new i am...  everything i see tells me that the board should work on a due/digix.  pins are the same  and not a lot of difference with the software right? so what's your take on his claim that it wont work with anything other than a mega. i assume his biggest issues is that the board is 5.5v who knows i could be wrong tis been known to happen :~D

[digistump]

It's a 5v board - that's a huge difference - you'd need to level shift all of the connections or redesign the whole board.


DigiX/Due is ARM, MEGA is AVR - completely different code required for all but the basic functionality - and a 3D printer uses a ton of non-basic functionality - here is a project to make RAMPS work on Due - lots of very experienced people working on it and it hasn't gone too far: http://reprap.org/wiki/RAMPS-FD - not to say it isn't doable - but at minmum your going to need a strong understanding of AVR and ARM, the specific chips and all of their registers, and C++ (nor Arduino, but real C/C++)


So in summary I'd agree with the seller - it requires a Mega - running it on Due/DigiX would require major circuit changes and probably nearly a rewrite of the firmware.

[vulcan2000]

 unfourtanate but....i just learned a lot... thanks

[Docedison]

I don't know how applicable this is but I've stacked a bunch of display shields up, On Mega's. I remove the single pin strips and replace them with stackable headers. It's really easy if you first remove the plastic retaining strip and then the pins one at a time.. This necessary to get at the extra com ports and I use a "screwshield" that Crossroads of Arduino Forum 'fame' sells. All this on a mega but it worked very well. I've looked for a Digix "Screw Shield" to no avail. I was also able to get a 320 X 240 line 3.2" display to work on an 8" 40 conductor cable which made implementing virtually anything easy. The display was the I/O device.. I'm giving strong thought to creating a shield like that with a dual row of screw terminals around the edges.

Doc