Datasheet

65
ATtiny828 [DATASHEET]
8371A–AVR–08/12
The illustration in the figure above serves as a generic description applicable to all port pins in the AVR microcontroller
family. Some overriding signals may not be present in all port pins.
Table 20 summarizes the function of the overriding signals. The pin and port indexes from Figure 25 on page 64 are not
shown in the succeeding tables. The overriding signals are generated internally in the modules having the alternative
function.
Table 20. Generic Description of Overriding Signals for Alternative Functions
The following subsections shortly describe the alternative functions for each port, and relate the overriding signals to the
alternative function. Refer to the alternative function description for further details.
10.3.1 Alternative Functions of Port A
The alternative functions of port A are shown in Table 21.
Signal 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 PUExn = 0b1.
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 PUExn Register bit.
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.
PTOE
Port Toggle Override
Enable
If PTOE is set, the PORTxn Register bit is inverted.
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 alternative 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
alternative function will use its own synchronizer.
AIO Analog Input/Output
This is the Analog Input/Output to/from alternative functions. The signal is
connected directly to the pad, and can be used bi-directionally.