Pin providing 2.5v insted of 3.3v


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Im using the Papilio Duo and pin 27(D27) is putting out 2.5v insted of 3.3v

any ideas why? in the code it gives out '1' so it should put out 3.3v.

Thank you!


You can't expect to see 3.3v on the output pin.


What IO standard are you using? LVTTL? LVCMOS33?


The Spartan-6 data sheet specifies that for LVTTL the Voh (V output high) is minimum 2.4V and for LVCMOS33 Voh is minimum Vcco - 0.4V (i.e. min 2.9V).  So if you are using LVTTL then 2.5V is well within spec.


For more info see Table 9 on page 10 in this data sheet:



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