I need two GPIO lines for a project on the smoothieboard in order to multiplex my 3 Z screws. I would better not use any pin which is used for displays or other existing hardware extension. Which are the most suitable?
I have no need for anything fancy here (no IRQ, no PWM, no fast switching, just plain and slow GPIOs).
Actually a plus would be an already soldered header (just for now for laziness) 
Was thinking about 1.30 and 1.31
+Peter van der Walt thanks for being so quick! But isn’t this a bit zealous (beside safety for the board)? TTL is OK for me, so I would better keep the mosfets for actuators.
+Peter van der Walt yes and yes… Now, using pins belonging to mosfets is a pity in case I need some later on, which is why unused raw pins are better for me 
… if there are any
Indeed… we’re probably going to be stuck – and we knew it --. We are looking into X + Y + (Z1+Z2+Z3) + E1 + E2 + E3 (+heaters) + Bed + 1-2 servos.
Now all Z are grouped thanks to multiplexing.
I think we will anyhow have to use a slave board in the end, because of this lack of GPIOs. Actually I probably can ditch the display, as I expect to link the SM with a Raspberry anyway (for a possibly stand-alone machine + wifi, etc: slicing must be possible on board).
http://smoothieware.org/pinout and http://smoothieware.org/lpc1769-pin-usage
I’d probably use the play/pause pins, nobody uses that.
I’m going to be doing exactly the same thing as you in a few weeks on a printer I’m building 
@Arthur_Wolf yep we have now two prototypes in which we have to put the Z and tool changer – too bad I am on holidays next week 
@Jeremie_Francois do you have any pics or videos of your prototype. It sounds fancy.
The play/pause pin is now an immediate kill function, and they are used by many people!! just FYI.
@Wolfmanjm yep I saw that (thx). No biggie for now. I will sacrify the lcd, since we’ll most probably use a raspberry for the slicing, user and web interaction.
@Mert_G not yet, but I will