Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
81
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
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 V
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 V
CC
or GND 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/Os.
shows how the port
pin control signals from the simplified
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.
all port pins in the AVR microcontroller family.
Figure 14-5.
Alternate Port Functions
Note:
1. WRx, WPx, WDx, RRx, RPx, and RDx are common to all pins within the same port. clk
I/O
, SLEEP, and PUD are
common to all ports. All other signals are unique for each pin.
clk
RPx
RRx
WRx
RDx
WDx
PUD
SYNCHRONIZER
WDx:
WRITE DDRx
WRx:
WRITE PORTx
RRx:
READ PORTx REGISTER
RPx:
READ PORTx PIN
PUD:
PULLUP DISABLE
clk
I/O
:
I/O CLOCK
RDx:
READ DDRx
D
L
Q
Q
SET
CLR
0
1
0
1
0
1
DIxn
AIOxn
DIEOExn
PVOVxn
PVOExn
DDOVxn
DDOExn
PUOExn
PUOVxn
PUOExn:
Pxn PULL-UP OVERRIDE ENABLE
PUOVxn:
Pxn PULL-UP OVERRIDE VALUE
DDOExn:
Pxn DATA DIRECTION OVERRIDE ENABLE
DDOVxn:
Pxn DATA DIRECTION OVERRIDE VALUE
PVOExn:
Pxn PORT VALUE OVERRIDE ENABLE
PVOVxn:
Pxn PORT VALUE OVERRIDE VALUE
DIxn:
DIGITAL INPUT PIN n ON PORTx
AIOxn:
ANALOG INPUT/OUTPUT PIN n ON PORTx
RESET
RESET
Q
Q
D
CLR
Q
Q
D
CLR
Q
Q
D
CLR
PINxn
PORTxn
DDxn
D
ATA
B
U
S
0
1
DIEOVxn
SLEEP
DIEOExn: Pxn DIGITAL INPUT-ENABLE OVERRIDE ENABLE
DIEOVxn: Pxn DIGITAL INPUT-ENABLE OVERRIDE VALUE
SLEEP:
DIEOVxn: Pxn DIGITAL INPUT-ENABLE OVERRIDE VALUE
SLEEP:
SLEEP CONTROL
Pxn
I/O
0
1
PTOExn
PTOExn:
Pxn, PORT TOGGLE OVERRIDE ENABLE
WPx:
WRITE PINx
WPx