[sebhc] ET-3400: Why missing pins on 40 pin expansion connector?

Timothy J. Weber tw at timothyweber.org
Fri Apr 27 09:05:12 CDT 2007

Whipaway wrote:
> Is there any reason that front row pins 1 and 2  and rear row pins 
> 3,4,6,7,8,,9,10,15 are omitted from the 40 pin expansion connector on 
> the ET-3400A:? (And ET-3400 after modification)

My guess is: they weren't needed for the ETA-3400.  Some of those are 
no-contact, and others are 6800 diagnostic lines that they didn't need.

But wait - 10 is omitted?  That's +5V in the ET-3400 schematic.  Seems 
pretty essential.

> Also, why are the RE and Clock2 signals available on 2 pins each (Isn't 
> one pin enough?)
> Are the equivalent pins that are omitted on the ETA-3400A / EWA-3400A 
> connected to anything?

No clue on these.
Timothy J. Weber
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