I need help deciphering this card edge connector's datasheet.

[MarkS]

I'm trying to create a library in KiCAD for AMP card edge connector 5650090-9. datasheet I need to create the schematic and footprint for both the card edge and the connector.

This is a 160 position connector. The issue is with the card edge diagram on page two. Looking at the drawing, I see that there are Y spaces, a notch, and then X spaces. Going back to page one, I see that Y is 37 and X is 41. 41 + 37 x 2 = 156. To make it even more confusing, the "NO OF DUAL POSN" column right next to the X column on page one says 80. 41 + 37 = 78! Where are the four missing connections? While I do not need all of the 160 connections for my project (future expansion), I would like to get this right before I waste money on a board. It looks like the notch would hide four connections easily, but then why sell this as a 160-position connector?

I must be reading this wrong!

[forrestc]

I'm trying to create a library in KiCAD for AMP card edge connector 5650090-9. datasheet I need to create the schematic and footprint for both the card edge and the connector.

This is a 160 position connector. The issue is with the card edge diagram on page two. Looking at the drawing, I see that there are Y spaces, a notch, and then X spaces. Going back to page one, I see that Y is 37 and X is 41. 41 + 37 x 2 = 156. To make it even more confusing, the "NO OF DUAL POSN" column right next to the X column on page one says 80. 41 + 37 = 78! Where are the four missing connections? While I do not need all of the 160 connections for my project (future expansion), I would like to get this right before I waste money on a board. It looks like the notch would hide four connections easily, but then why sell this as a 160-position connector?

This appears to be a fencepost error.  Look it up if you don't know this term....

The sheet says 'X spaces', not 'X holes'.

If you want to be sure about this, get a connector and count.... but that's my best guess

[rs20]

You have five fingers, but only four gaps between your five fingers.

(41 + 1) + (37 + 1) = 80

[MarkS]

I mistook spaces for positions of the contacts. That makes sense.

[WastelandTek]

And I learned a term..."fencepost error"   excellent

[MarkS]

Also known in the programming world as the "Off-by-one error."