RAMPS Schematic questions (5 replies)

Hi all-

I am trying to study the RAMPS/Mega2560 schematic to learn more about how the pins are assigned so I can understand the pin assignments in Marlin.

I am using plain vanilla RAMPS 1.4 + Mega2560. I have specified ramps_efb in the config and my printer works just fine. I am considering adding the fan expander or an XB so this is why i am trying to figure this out.

I am really confused about the numbers that the pins are assigned with. For example pins 60, 61 for Y-step and Y-enable. Looking at the schematic, I see where they are assigned.

[attachment 103938 RAMPS1.4schematic.png]

Then I look at the schematic of the shield- [attachment 103939 Ramps_v1.4_shield_bothsides.png] and I see that the pins for Y-step and Y-enable are connected to PK6 & PK7, and looking at the Mega2560 pin assignments I see that those pins are combination pins, but their physical pin numbers are 83 & 82, PCIO22 & 23. So now I am really confused.
[attachment 103940 MegaPinOut.png]

Pins 60 on the Mega is PC7/A15 and it routes to E0 Direction pin.


Is there a different schematic I should be referencing? What am I not understanding?