ATMEGA128A-MU Atmel, ATMEGA128A-MU Datasheet - Page 71

• Manufacturer Part Number: ATMEGA128A-MU
• Description: MCU 8BIT 128K ISP FLASH 64-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA128A-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATMEGA128x
• Core: AVR8
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Controller Family/series: AVR MEGA
• No. Of I/o's: 53
• Eeprom Memory Size: 4KB
• Ram Memory Size: 4KB
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

12.2.4
12.3
8151H–AVR–02/11
Alternate Port Functions
Unconnected pins
If some pins are unused, it is recommended to ensure that these pins have a defined level. Even
though most of the digital inputs are disabled in the deep sleep modes as described above, float-
ing inputs should be avoided to reduce current consumption in all other modes where the digital
inputs are enabled (Reset, Active mode 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 V
accidentally configured as an output.
Most port pins have alternate functions in addition to being general digital I/Os.
shows how the port pin control signals from the simplified
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 12-6. Alternate Port Functions
PUOExn:
PUOVxn:
DDOExn:
DDOVxn:
PVOExn:
PVOVxn:
DIEOExn: Pxn DIGITAL INPUT-ENABLE OVERRIDE ENABLE
DIEOVxn: Pxn DIGITAL INPUT-ENABLE OVERRIDE VALUE
SLEEP:
CC
Pxn
or GND is not recommended, since this may cause excessive currents if the pin is
Pxn PULL-UP OVERRIDE ENABLE
Pxn PULL-UP OVERRIDE VALUE
Pxn DATA DIRECTION OVERRIDE ENABLE
Pxn DATA DIRECTION OVERRIDE VALUE
Pxn PORT VALUE OVERRIDE ENABLE
Pxn PORT VALUE OVERRIDE VALUE
SLEEP CONTROL
1
0
1
0
1
0
1
0
(1)
PUOExn
PUOVxn
DDOExn
DDOVxn
PVOExn
PVOVxn
DIEOExn
DIEOVxn
SLEEP
PUD:
WDx:
RDx:
RRx:
WPx:
RPx:
clk
DIxn:
AIOxn:
SYNCHRONIZER
D
L
I/O
SET
CLR
:
Q
Q
PULLUP DISABLE
WRITE DDRx
READ DDRx
READ PORTx REGISTER
WRITE PORTx
READ PORTx PIN
I/O CLOCK
DIGITAL INPUT PIN n ON PORTx
ANALOG INPUT/OUTPUT PIN n ON PORTx
D
PINxn
CLR
Figure 12-2
Q
Q
RESET
RESET
PORTxn
Q
Q
Q
Q
DDxn
CLR
CLR
D
D
ATmega128A
can be overridden by
clk
PUD
WDx
RDx
WPx
RRx
DIxn
AIOxn
RPx
I/O
Figure 12-6
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