Hi @tommino,
The LPC82x User Manual states what pins are 5V tolerant on "Table 405. Pin description". Specifically, look at the footnotes of the 4th column in that table. In general, if the pin has a [2], [3], [4], [5] or [8] footnote, it is 5V tolerant (see the footnotes for exceptions of each).
BR,
Edwin.