ATXMEGA128A4 Datasheet, PDF (26/69 Pages) ATMEL Corporation – 8/16-bit XMEGA A4 Microcontroller

14.3.1 Push-pull
Figure 14-1. I/O configuration - Totem-pole
DIRn
OUTn
INn
XMEGA A4
Pn
14.3.2 Pull-down
Figure 14-2. I/O configuration - Totem-pole with pull-down (on input)
DIRn
OUTn
Pn
INn
14.3.3 Pull-up
Figure 14-3. I/O configuration - Totem-pole with pull-up (on input)
DIRn
OUTn
Pn
INn
14.3.4
Bus-keeper
The bus-keeper’s weak output produces the same logical level as the last output level. It acts as
a pull-up if the last level was ‘1’, and pull-down if the last level was ‘0’.
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