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Old 17th Sep 2020, 1:57 pm   #45
Slothie
Heptode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 543
Default Re: I found it !. A very sorry looking MK14

Its worth noting that on the MK14 only D0..D3 have pullups to +5v, so when the data bus goes tristate D0..D3 will go to +5v but D4..D7 will do whatever they like. Something else on the bus may be pulling these lines weakly to odd levels, or capacitive coupling or........
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