RAMPS Schematic questions

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.



Then I look at the schematic of the shield- 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.


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?

Edited 2 time(s). Last edit at 04/02/2018 12:30PM by sinned.

Small observation, did you write the PK-0 to PK7 yourself on the 2nd picture? Because those are PF-0 to PF-7
RAMPS1.4 and Mega2560 are identical in size and their mounting holes match.

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]

Yes, I did try to write the pin assignments myself. I will admit, it was quite late when I did that and might have made mistake, but I wrote them based on the mapping that I found in the second picture that I posted. Is that one incorrect?


The picture that you posted- how should I have found that?

That seems to answer my lingering questions.

sinneD

Quote
sinned
The picture that you posted- how should I have found that?

sinneD

I use this thing

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]

i meant the search terms.

i have been searching for "mega2560 digital pins", "mega2560 pin map" and other varients and getting nowhere.

my stumbling block seems to be getting the right search term.

The word you need to use is "pinout", no need to for digital/analogs/maps, just "pinout"

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]