Rainbow Electronics ATmega128RFA1 - Manual (Page 191)

191
8266A-MCU Wireless-12/09
ATmega128RFA1
described above, floating inputs should be avoided to reduce current consumption in all
other modes where the digital inputs are enabled (Reset-, Active- and Idle-mode).
The simplest method to ensure a defined level of an unused pin is to enable the internal
pull-up. In this case, the pull-up will be disabled during reset. If low power consumption
during reset is important, it is recommended to use an external pull-up or pull-down.
Connecting unused pins directly to DEVDD or DVSS is not recommended, since this
may cause excessive currents if the pin is accidentally configured as an output.
14.3 Alternate Port Functions
Most port pins have alternate functions in addition to being general digital I/O ports.
Figure 14-5 below shows how the port pin control signals from the simplified Figure
14-2 on page 187 can be overridden by alternate functions. The overriding signals may
not be present in all port pins, but the figure serves as a generic description applicable
to all port pins in the AVR microcontroller family.
Figure 14-5. Alternate Port Functions
(1)