Datasheet

134
XMEGA B [DATASHEET]
8291B–AVR–01/2013
12.8 Alternate Port Functions
Most port pins have alternate pin functions in addition to being a general purpose I/O pin. When an alternate function is
enabled, it might override the normal port pin function or pin value. This happens when other peripherals that require pins
are enabled or configured to use pins. If and how a peripheral will override and use pins is described in the section for
that peripheral.
The port override signals and related logic (grey) are shown in Figure 12-10 on page 134. These signals are not
accessible from software, but are internal signals between the overriding peripheral and the port pin.
Figure 12-10. Port override signals and related logic.
D
Q
R
D
Q
R
Synchronizer
D
Q
R
D
Q
R
DIRn
OUTn
PINnCTRL
INn
Pxn
D
Q
R
C
o
n
t
r
o
l
L
o
g
i
c
Digital Input Disable (DID)
Wired AND/OR
Digital Input Pin
Analog Input/Output
Inverted I/O
Pull Enable
Pull Keep
Pull Direction
DID Override Enable
DID Override Value
OUT Override Enable
OUT Override Value
DIR Override Enable
DIR Override Value