Different board layout for alternative to mbed
I have a reprap, laser K40-III (moshi) and at some point in the future, hopefully a homebrew CNC. I did hook up a RAMPS/mega board to the laser but it isn't really going to cut it... I'm thinking that having a shared platform between them and therefore re-spinning the LAOS PCB to take something other than the mbed. Ethernet, touch screens would be nice to have. From a brief search, I've stumbled on a couple of possibilities that appear to have merit:
1. A cheap LPC1768 (£20) (not 1769) dev board, onboard ethernet, sdcard, with plenty spare pins on the headers: http://www.ebay.co.uk/itm/NXP-ARM-Cortex-M3-LPC1768-Mini-DK2-Development-board-/181045434143?pt=LH_DefaultDomain_0&hash=item2a2726171f and a random touchscreen LCD (£10-15) http://www.ebay.co.uk/itm/3-2-TFT-LCD-Display-Touch-Panel-PCB-adapter-SD-Slot-for-Arduino-Mega2560-R3-/281185062954?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item4177ef902a
2. And expresso_smoothie: http://reprap.org/wiki/Xpresso_Smoothie
I'm tempted to combine the two, i.e. spin a board that can take the headers from the cheap board and provide a Smoothie/LAOS hybrid and also have a connector for the touch screen, using old IDE cables to join it all up allowing the touchscreen to be a little away from the controller. The cheap board provides the ethernet, sdcard etc.
Are there any other considerations apart from having the laser PWM on a HW PWM pin (which the smoothie does on its mosfet outputs)? i.e. can all other pins be remapped easily enough? Is the 1768 a problem other than clock speed? Should I do something else entirely? etc. etc.