ATMEGA323-8PI Atmel, ATMEGA323-8PI Datasheet - Page 137

• Manufacturer Part Number: ATMEGA323-8PI
• Description: IC AVR MCU 32K 8MHZ IND 40DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA323-8PI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA3238PI

I/O Ports
Port A
The Port A Data Register –
PORTA
The Port A Data Direction
Register – DDRA
The Port A Input Pins Address
– PINA
1457G–AVR–09/03
All AVR ports have true Read-Modify-Write functionality when used as general digital
I/O ports. This means that the direction of one port pin can be changed without uninten-
tionally changing the direction of any other pin with the SBI and CBI instructions. The
same applies for changing drive value (if configured as output) or enabling/disabling of
pull-up resistors (if configured as input).
Port A is an 8-bit bi-directional I/O port with optional internal pull-ups.
Three I/O Memory address locations are allocated for Port A, one each for the Data
Register – PORTA, $1B($3B), Data Direction Register – DDRA, $1A($3A) and the Port
A Input Pins – PINA, $19($39). The Port A Input Pins address is read only, while the
Data Register and the Data Direction Register are read/write.
All port pins have individually selectable pull-up resistors. The Port A output buffers can
sink 20 mA and thus drive LED displays directly. When pins PA0 to PA7 are used as
inputs and are externally pulled low, they will source current if the internal pull-up resis-
tors are activated.
Port A has an alternate function as analog inputs for the ADC. If some Port A pins are
configured as outputs, it is essential that these do not switch when a conversion is in
progress. This might corrupt the result of the conversion.
During Power-down mode, the Schmitt Trigger of the digital input is disconnected. This
allows analog signals that are close to V
causing excessive power consumption.
The Port A Input Pins address – PINA – is not a register, and this address enables
access to the physical value on each Port A pin. When reading PORTA the Port A Data
Latch is read, and when reading PINA, the logical values present on the pins are read.
Bit
$1B ($3B)
Read/Write
Initial Value
Bit
$1A ($3A)
Read/Write
Initial Value
Bit
$19 ($39)
Read/Write
Initial Value
PORTA7
PINA7
DDA7
R/W
R/W
N/A
7
0
7
R
7
0
PORTA6
PINA6
DDA6
R/W
R/W
N/A
R
6
0
6
6
0
PORTA5
PINA5
DDA5
R/W
R/W
N/A
R
5
0
5
5
0
PORTA4
PINA4
DDA4
R/W
R/W
N/A
R
4
0
4
4
0
CC
/2 to be present during Power-down without
PORTA3
DDA3
PINA3
R/W
R/W
N/A
3
0
R
3
3
0
PORTA2
DDA2
PINA2
R/W
R/W
N/A
2
0
R
2
2
0
ATmega323(L)
PORTA1
DDA1
PINA1
R/W
R/W
N/A
1
0
R
1
1
0
PORTA0
DDA0
PINA0
R/W
R/W
N/A
0
0
R
0
0
0
PORTA
DDRA
PINA
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