On 1/10/2010 2:59 AM, ivp wrote:
> Forrest, do the ATF pins have high enough capacitance to degrade
> the programming lines ?
>    
According to the ATF datasheet, the capacitance is 8pf on each 
line...    Input current is 10uA.

Ooooh, ick... I had forgotten about this..  the ATF's have a pin-keeper 
circuit where it drives the input with the last seen input through an 
active driver and a 100K resistor... basically makes the inputs 'sticky' 
so that a floating pin doesn't float.   This means that the inputs are 
effectively always pulled up or down with a 100K internal resistor...    
Although I wouldn't think that a 100K pullup or pulldown would be enough 
to mess up programming, I guess with the newer faster ICD, that makes 
some sense.

-forrest
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