Datasheet

131
XMEGA B [DATASHEET]
8291B–AVR–01/2013
12.4 Reading the Pin Value
Independent of the pin data direction, the pin value can be read from the IN register, as shown in Figure 12-1 on page
127. If the digital input is disabled, the pin value cannot be read. The IN register bit and the preceding flip-flop constitute
a synchronizer. The synchronizer introduces a delay on the internal signal line. Figure 12-8 on page 131 shows a timing
diagram of the synchronization when reading an externally applied pin value. The maximum and minimum propagation
delays are denoted as t
pd,max
and t
pd,min
, respectively.
Figure 12-8. Synchronization when reading a pin value.