mysterious button on reprapdiscount smart controller

Hi!

I'm building custom prusa i3 3d printers for my kids (4 kids + myself = 5) (intended as Christmas presents, but things are running longer than expected :-) ) I have a working i2 and most of the parts.

I'm using reprapdiscount smart controllers (probably copies of originals - came from one of the better Chinese sources)

They work nicely, but have a mysterious button below the knob that hangs the printer whenever it is pushed. (have to unplug/replug or press reset on the ramps 1.4 to bring it alive again)

The hanging only occurrs with Marlin installed. When I run repetier the button acts like a reset button which is a desired effect.

I'd hate to disable this button since its there, nice and handy, and don't want to use the (very good) repetier firmware since I'm trying to stay open source in case I make something I want to sell and support some day. I also prefer marlin's smooth motions when manually moving the printer on its axis.

In case the reader isn't sure what I'm talking about, I have included a picture of one such controller with a 3d printed fox looking at the mysterious switch.

I there anyone who has been down this path ahead of me who can fling some wisdom my way? Thanx. :-)

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I am. Therefore I build. - Mendell/Prusa 2 User

I am not sure if it is supposed to be a reset button or just an emergency stop button. However, if I had to guess I would think that the pin assignments between the Marlin and Repieter firmwares are different. So when you hit the button in Marlin, you are triggering pin X throwing some kind of error (or hitting the emergency stop, shutting down everything), and in Repieter, you are triggering pin Y which is the reset button by default.

Try checking the uiconfig.h files which is where the LCD is configured I believe. You might also try referencing pins.h to see what pins are already assigned functions.

Haven't started playing with my LCD yet, so I can't offer much more.

Under marlin on my prusa i2.
Its an emergency stop switch. It immediatly stops the stepper motors in case it overuns a stop switch
or in other ways could damage your machine. On my prusa i2 one of the z motor wires came loose and started to twist in the frame.
Using the stop switch prevented a lot of damage.
You then need to reset the controller to free it up.

I think its hooked up to an inturupt on the arduino controller so that no matter what the controller is doing it will
immediately inturupt the processor to bring it to an immediate stop. Thats why it seems to be locked up and un responsive.

Gordon

Edited 1 time(s). Last edit at 01/07/2015 06:19PM by gordonendersby.

First I would like to thank you for your time. :-) Your description is exactly consistant with my experience. You make it sound like the "mystery button" produces a direct interupt to the processor and does not rely on code to "MAKE IT STOP!!'. With your own experience as an example, that is a very good thing since code is not 100% reliable. I guess the difference between repetier's auto-reset and marlin's percieved hanging is how they handle stop interupts in general and not a pin setting. It is going to take a bit of consideration for me to start prefering this behavior. I guess it could prevent trouble if the system had a propensity to do things imediately after a reset. :-) Perhaps I'll just get used to its behavior and stop trying to "fix" it. :-) Anyway this is what I'm getting from all my experiences and people's help. Please redirect me If I'm going down a wrong path. Thanks again!! :-)

Just one more example of my struggling on and on trying to do something that turns out to be dificult or impossible and realizing later that it is that way because it is a bad idea to do it. :-)