I've recently added pin mappings to complement the original mappings which were for mega644.
It looks as if pin 15, which is what Marlin maps Z_MAX_PIN to for RAMPS 1.4 boards, starts out high (logically high; my configuration has pullups enabled, so endstops are "inverting"). This shouldn't happen since the starting position is less than the max configured in reprap.c.
The evidence for this is that an initial M119 after starting up reports Z_MAX as TRIGGERED. (It's possible that this has nothing to do with the pin, I'm not sure how to test that hypothesis.)
I've recently added pin mappings to complement the original mappings which were for mega644.
It looks as if pin 15, which is what Marlin maps Z_MAX_PIN to for RAMPS 1.4 boards, starts out high (logically high; my configuration has pullups enabled, so endstops are "inverting"). This shouldn't happen since the starting position is less than the max configured in reprap.c.
The evidence for this is that an initial M119 after starting up reports Z_MAX as TRIGGERED. (It's possible that this has nothing to do with the pin, I'm not sure how to test that hypothesis.)