... a bit ambiguous this. Comparing the v2.8 PCB with the All In One Schematics on the first page of this post shows the mistake in the schematic - or is it the PBC marking?
From Dmitris' Megadrum32 Digital board schema 21/7/08 he's using the weak pull ups and gets:
mCu pin - connector pin - button (0v)
6 ------------- 1 ------------- up
7 ------------- 2 ------------- down
8 ------------- 3 ------------- left
--------------- 4 -------------GND
6&7 -------------------------- right (two diode rejection thingy)
All is well.
In the Synthex PCB v2.8 Quick Manual.pdf (and else where) his keyboard connector is doc'd thus:
1 - Right
2 - Up
3 - Down
4 - Left
5 - GND
The two diodes are mounted and I assume the firmware is the same - so why the extra pin?
A continuity test for the v2.8 PCB show this:
mCu pin - connector pin - button (0v)
6 ------------- 2 ------------- up
7 ------------- 3 ------------- down
8 ------------- 4 ------------- left
--------------- 5 ------------- GND
6&7 ----------- 1 ------------- right (two diode rejection thingy)
So at the very least the v2.8 pcb keyboard connector should be marked topside as 43215