Datasheet

Table 18-2. Generic Description of Overriding Signals for Alternate Functions
Signal
Name
Full Name Description
PUOE Pull-up Override
Enable
If this signal is set, the pull-up enable is controlled by the PUOV signal. If this
signal is cleared, the pull-up is enabled when {DDxn, PORTxn, PUD} = 0b010.
PUOV Pull-up Override
Value
If PUOE is set, the pull-up is enabled/disabled when PUOV is set/cleared,
regardless of the setting of the DDxn, PORTxn, and PUD Register bits.
DDOE Data Direction
Override Enable
If this signal is set, the Output Driver Enable is controlled by the DDOV signal. If
this signal is cleared, the Output driver is enabled by the DDxn Register bit.
DDOV Data Direction
Override Value
If DDOE is set, the Output Driver is enabled/disabled when DDOV is set/cleared,
regardless of the setting of the DDxn Register bit.
PVOE Port Value
Override Enable
If this signal is set and the Output Driver is enabled, the port value is controlled
by the PVOV signal. If PVOE is cleared, and the Output Driver is enabled, the
port Value is controlled by the PORTxn Register bit.
PVOV Port Value
Override Value
If PVOE is set, the port value is set to PVOV, regardless of the setting of the
PORTxn Register bit.
DIEOE Digital Input
Enable Override
Enable
If this bit is set, the Digital Input Enable is controlled by the DIEOV signal. If this
signal is cleared, the Digital Input Enable is determined by MCU state (Normal
mode, sleep mode).
DIEOV Digital Input
Enable Override
Value
If DIEOE is set, the Digital Input is enabled/disabled when DIEOV is set/cleared,
regardless of the MCU state (Normal mode, sleep mode).
DI Digital Input This is the Digital Input to alternate functions. In the figure, the signal is
connected to the output of the Schmitt Trigger but before the synchronizer.
Unless the Digital Input is used as a clock source, the module with the alternate
function will use its own synchronizer.
AIO Analog Input/
Output
This is the Analog Input/output to/from alternate functions. The signal is
connected directly to the pad and can be used bi-directionally.
The following subsections shortly describe the alternate functions for each port and relate the overriding
signals to the alternate function. Refer to the alternate function description for further details.
18.3.1 Alternate Functions of Port B
The Port B pins with alternate functions are shown in the table below:
Table 18-3. Port B Pins Alternate Functions
Port Pin Alternate Functions
PB7
XTAL2 (Chip Clock Oscillator pin 2)
TOSC2 (Timer Oscillator pin 2)
ATmega48PA/88PA/168PA
I/O-Ports
© 2018 Microchip Technology Inc.
Datasheet Complete
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