55
8126F–AVR–05/12
ATtiny13A
The overriding signals may not be present in all port pins, but Figure 10-5 serves as a generic
description applicable to all port pins in the AVR microcontroller family.
Table 10-2 on page 55 summarizes the function of the overriding signals. The pin and port
indexes from Figure 10-5 on page 54 are not shown in the succeeding tables. The overriding
signals are generated internally in the modules having the alternate function.
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.
10.3.1 Alternate Functions of Port B
The Port B pins with alternate function are shown in Table 10-3 on page 56.
Table 10-2. 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.
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 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.
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