Datasheet

128
XMEGA B [DATASHEET]
8291B–AVR–01/2013
configurations with pull-up and pull-down have active resistors only when the pin is set as input. This feature eliminates
unnecessary power consumption. For wired-AND and wired-OR configuration, the optional pull-up and pull-down
resistors are active in both input and output directions.
Since pull configuration is configured through the pin configuration register, all intermediate port states during switching
of the pin direction and pin values are avoided.
The I/O pin configurations are summarized with simplified schematics in Figure 12-2 on page 128 to Figure 12-7 on page
130.
12.3.1 Totem-pole
In the totem-pole (push-pull) configuration, the pin is driven low or high according to the corresponding bit setting in the
OUT register. In this configuration, there is no current limitation for sink or source other than what the pin is capable of. If
the pin is configured for input, the pin will float if no external pull resistor is connected.
Figure 12-2. I/O pin configuration - Totem-pole (push-pull).
12.3.1.1 Totem-pole with Pull-down
In this mode, the configuration is the same as for totem-pole mode, expect the pin is configured with an internal pull-down
resistor when set as input.
Figure 12-3. I/O pin configuration - Totem-pole with pull-down (on input).