Can anyone tell me where I can find documentation on the SERVOS, AUX1, 2 & 3 pins of a RAMPS1.4? Looking at the odd trace I suspect some of the Mega analogue pins are linked there. I’ve tried the RepRap Wiki, Google, etc and I’m not getting anywhere. I have my load cell sitting under my spool patiently waiting to be wired up…
Just take a look at this image http://www.reprap.org/wiki/File:Arduinomega1-4connectors.png. It contains the full pinout of those connectors.
Many thanks!
Cool A3 or A4 on AUX1 look the best bet. Now to hunt through the Marlin source to see how A13/14 are read to get thermistor values.
Look at https://github.com/ErikZalm/Marlin/blob/Marlin_v1/Marlin/temperature.cpp around line 1183 is the ISR which reads all (configured) analog inputs asynchronously. Also there is a init around line 769 to setup the analog inputs. You can add your own sensor here, but that ofcourse needs some extensions in the various storage locations. Or you can just read the sensor synchronously with analogRead(A3), for example as a reaction to a mcode in marlin_main.cpp