Features
• High Performance, Low Power AVR® 8-Bit Microcontroller
• Advanced RISC Architecture
•
•
•
•
•
•
•
•
– 131 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
– Up to 20 MIPS Throughput at 20 MHz
– On-chip 2-cycle Multiplier
High Endurance Non-volatile Memory Segments
– 4/8/16/32K Bytes of In-System Self-Programmable Flash progam memory
(ATmega48PA/88PA/168PA/328P)
– 256/512/512/1K Bytes EEPROM (ATmega48PA/88PA/168PA/328P)
– 512/1K/1K/2K Bytes Internal SRAM (ATmega48PA/88PA/168PA/328P)
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– Programming Lock for Software Security
Peripheral Features
– Two 8-bit Timer/Counters with Separate Prescaler and Compare Mode
– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture
Mode
– Real Time Counter with Separate Oscillator
– Six PWM Channels
– 8-channel 10-bit ADC in TQFP and QFN/MLF package
Temperature Measurement
– 6-channel 10-bit ADC in PDIP Package
Temperature Measurement
– Programmable Serial USART
– Master/Slave SPI Serial Interface
– Byte-oriented 2-wire Serial Interface (Philips I2C compatible)
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
– Interrupt and Wake-up on Pin Change
Special Microcontroller Features
– Power-on Reset and Programmable Brown-out Detection
– Internal Calibrated Oscillator
– External and Internal Interrupt Sources
– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby,
and Extended Standby
I/O and Packages
– 23 Programmable I/O Lines
– 28-pin PDIP, 32-lead TQFP, 28-pad QFN/MLF and 32-pad QFN/MLF
Operating Voltage:
– 1.8 - 5.5V for ATmega48PA/88PA/168PA/328P
Temperature Range:
– -40°C to 85°C
Speed Grade:
– 0 - 20 MHz @ 1.8 - 5.5V
Low Power Consumption at 1 MHz, 1.8V, 25°C for ATmega48PA/88PA/168PA/328P:
– Active Mode: 0.2 mA
– Power-down Mode: 0.1 µA
– Power-save Mode: 0.75 µA (Including 32 kHz RTC)
8-bit
Microcontroller
with 4/8/16/32K
Bytes In-System
Programmable
Flash
ATmega48PA
ATmega88PA
ATmega168PA
ATmega328P
Summary
Rev. 8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
1. Pin Configurations
Figure 1-1.
Pinout ATmega48PA/88PA/168PA/328P
PDIP
32
31
30
29
28
27
26
25
PD2 (INT0/PCINT18)
PD1 (TXD/PCINT17)
PD0 (RXD/PCINT16)
PC6 (RESET/PCINT14)
PC5 (ADC5/SCL/PCINT13)
PC4 (ADC4/SDA/PCINT12)
PC3 (ADC3/PCINT11)
PC2 (ADC2/PCINT10)
TQFP Top View
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
ADC7
GND
AREF
ADC6
AVCC
PB5 (SCK/PCINT5)
(PCINT21/OC0B/T1) PD5
(PCINT22/OC0A/AIN0) PD6
(PCINT23/AIN1) PD7
(PCINT0/CLKO/ICP1) PB0
(PCINT1/OC1A) PB1
(PCINT2/SS/OC1B) PB2
(PCINT3/OC2A/MOSI) PB3
(PCINT4/MISO) PB4
9
10
11
12
13
14
15
16
PD2 (INT0/PCINT18)
PD1 (TXD/PCINT17)
PD0 (RXD/PCINT16)
PC6 (RESET/PCINT14)
PC5 (ADC5/SCL/PCINT13)
PC4 (ADC4/SDA/PCINT12)
PC3 (ADC3/PCINT11)
PC2 (ADC2/PCINT10)
PC2 (ADC2/PCINT10)
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
GND
AREF
AVCC
PB5 (SCK/PCINT5)
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
ADC7
GND
AREF
ADC6
AVCC
PB5 (SCK/PCINT5)
9
10
11
12
13
14
15
16
8
9
10
11
12
13
14
(PCINT22/OC0A/AIN0) PD6
(PCINT23/AIN1) PD7
(PCINT0/CLKO/ICP1) PB0
(PCINT1/OC1A) PB1
(PCINT2/SS/OC1B) PB2
(PCINT3/OC2A/MOSI) PB3
(PCINT4/MISO) PB4
NOTE: Bottom pad should be soldered to ground.
PC5 (ADC5/SCL/PCINT13)
PC4 (ADC4/SDA/PCINT12)
PC3 (ADC3/PCINT11)
PC2 (ADC2/PCINT10)
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
GND
AREF
AVCC
PB5 (SCK/PCINT5)
PB4 (MISO/PCINT4)
PB3 (MOSI/OC2A/PCINT3)
PB2 (SS/OC1B/PCINT2)
PB1 (OC1A/PCINT1)
32
31
30
29
28
27
26
25
PD2 (INT0/PCINT18)
PD1 (TXD/PCINT17)
PD0 (RXD/PCINT16)
PC6 (RESET/PCINT14)
PC5 (ADC5/SCL/PCINT13)
PC4 (ADC4/SDA/PCINT12)
PC3 (ADC3/PCINT11)
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
28
27
26
25
24
23
22
21
20
19
18
17
16
15
32 MLF Top View
28 MLF Top View
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
VCC
GND
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
(PCINT21/OC0B/T1) PD5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
NOTE: Bottom pad should be soldered to ground.
(PCINT21/OC0B/T1) PD5
(PCINT22/OC0A/AIN0) PD6
(PCINT23/AIN1) PD7
(PCINT0/CLKO/ICP1) PB0
(PCINT1/OC1A) PB1
(PCINT2/SS/OC1B) PB2
(PCINT3/OC2A/MOSI) PB3
(PCINT4/MISO) PB4
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
(PCINT14/RESET) PC6
(PCINT16/RXD) PD0
(PCINT17/TXD) PD1
(PCINT18/INT0) PD2
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
VCC
GND
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
(PCINT21/OC0B/T1) PD5
(PCINT22/OC0A/AIN0) PD6
(PCINT23/AIN1) PD7
(PCINT0/CLKO/ICP1) PB0
2
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
1.1
1.1.1
Pin Descriptions
VCC
Digital supply voltage.
1.1.2
GND
Ground.
1.1.3
Port B (PB7:0) XTAL1/XTAL2/TOSC1/TOSC2
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port B output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port B pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port B pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Depending on the clock selection fuse settings, PB6 can be used as input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
Depending on the clock selection fuse settings, PB7 can be used as output from the inverting
Oscillator amplifier.
If the Internal Calibrated RC Oscillator is used as chip clock source, PB7..6 is used as TOSC2..1
input for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is set.
The various special features of Port B are elaborated in ”Alternate Functions of Port B” on page
76 and ”System Clock and Clock Options” on page 26.
1.1.4
Port C (PC5:0)
Port C is a 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
PC5..0 output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port C pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port C pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
1.1.5
PC6/RESET
If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the electrical characteristics of PC6 differ from those of the other pins of Port C.
If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. A low level on this pin
for longer than the minimum pulse length will generate a Reset, even if the clock is not running.
The minimum pulse length is given in Table 28-3 on page 308. Shorter pulses are not guaranteed to generate a Reset.
The various special features of Port C are elaborated in ”Alternate Functions of Port C” on page
79.
1.1.6
Port D (PD7:0)
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port D output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port D pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port D pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
3
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
The various special features of Port D are elaborated in ”Alternate Functions of Port D” on page
82.
1.1.7
AVCC
AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6. It should be externally
connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC
through a low-pass filter. Note that PC6..4 use digital supply voltage, VCC.
1.1.8
AREF
AREF is the analog reference pin for the A/D Converter.
1.1.9
ADC7:6 (TQFP and QFN/MLF Package Only)
In the TQFP and QFN/MLF package, ADC7:6 serve as analog inputs to the A/D converter.
These pins are powered from the analog supply and serve as 10-bit ADC channels.
4
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
2. Overview
The ATmega48PA/88PA/168PA/328P is a low-power CMOS 8-bit microcontroller based on the
AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the
ATmega48PA/88PA/168PA/328P achieves throughputs approaching 1 MIPS per MHz allowing
the system designer to optimize power consumption versus processing speed.
Block Diagram
Block Diagram
GND
Figure 2-1.
VCC
2.1
Watchdog
Timer
Watchdog
Oscillator
Oscillator
Circuits /
Clock
Generation
Power
Supervision
POR / BOD &
RESET
debugWIRE
Flash
SRAM
PROGRAM
LOGIC
CPU
EEPROM
AVCC
AREF
DATABUS
GND
8bit T/C 0
16bit T/C 1
A/D Conv.
8bit T/C 2
Analog
Comp.
Internal
Bandgap
USART 0
SPI
TWI
PORT D (8)
PORT B (8)
PORT C (7)
2
6
RESET
XTAL[1..2]
PD[0..7]
PB[0..7]
PC[0..6]
ADC[6..7]
The AVR core combines a rich instruction set with 32 general purpose working registers. All the
32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent
registers to be accessed in one single instruction executed in one clock cycle. The resulting
5
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.
The ATmega48PA/88PA/168PA/328P provides the following features: 4/8/16/32K bytes of InSystem Programmable Flash with Read-While-Write capabilities, 256/512/512/1K bytes
EEPROM, 512/1K/1K/2K bytes SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes, internal and external
interrupts, a serial programmable USART, a byte-oriented 2-wire Serial Interface, an SPI serial
port, a 6-channel 10-bit ADC (8 channels in TQFP and QFN/MLF packages), a programmable
Watchdog Timer with internal Oscillator, and five software selectable power saving modes. The
Idle mode stops the CPU while allowing the SRAM, Timer/Counters, USART, 2-wire Serial Interface, SPI port, and interrupt system to continue functioning. The Power-down mode saves the
register contents but freezes the Oscillator, disabling all other chip functions until the next interrupt or hardware reset. In Power-save mode, the asynchronous timer continues to run, allowing
the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O modules except asynchronous timer and ADC, to minimize
switching noise during ADC conversions. In Standby mode, the crystal/resonator Oscillator is
running while the rest of the device is sleeping. This allows very fast start-up combined with low
power consumption.
The device is manufactured using Atmel’s high density non-volatile memory technology. The
On-chip ISP Flash allows the program memory to be reprogrammed In-System through an SPI
serial interface, by a conventional non-volatile memory programmer, or by an On-chip Boot program running on the AVR core. The Boot program can use any interface to download the
application program in the Application Flash memory. Software in the Boot Flash section will
continue to run while the Application Flash section is updated, providing true Read-While-Write
operation. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on a
monolithic chip, the Atmel ATmega48PA/88PA/168PA/328P is a powerful microcontroller that
provides a highly flexible and cost effective solution to many embedded control applications.
The ATmega48PA/88PA/168PA/328P AVR is supported with a full suite of program and system
development tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators,
In-Circuit Emulators, and Evaluation kits.
2.2
Comparison Between ATmega48PA, ATmega88PA, ATmega168PA and ATmega328P
The ATmega48PA, ATmega88PA, ATmega168PA and ATmega328P differ only in memory
sizes, boot loader support, and interrupt vector sizes. Table 2-1 summarizes the different memory and interrupt vector sizes for the three devices.
Table 2-1.
Memory Size Summary
Device
Flash
EEPROM
RAM
Interrupt Vector Size
ATmega48PA
4K Bytes
256 Bytes
512 Bytes
1 instruction word/vector
ATmega88PA
8K Bytes
512 Bytes
1K Bytes
1 instruction word/vector
ATmega168PA
16K Bytes
512 Bytes
1K Bytes
2 instruction words/vector
ATmega328P
32K Bytes
1K Bytes
2K Bytes
2 instruction words/vector
ATmega88PA, ATmega168PA and ATmega328P support a real Read-While-Write Self-Programming mechanism. There is a separate Boot Loader Section, and the SPM instruction can
only execute from there. In ATmega48PA, there is no Read-While-Write support and no separate Boot Loader Section. The SPM instruction can execute from the entire Flash.
6
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
3. Resources
A comprehensive set of development tools, application notes and datasheets are available for
download on http://www.atmel.com/avr.
Note:
1.
4. Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less
than 1 PPM over 20 years at 85°C or 100 years at 25°C.
7
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
5. Register Summary
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(0xFF)
Reserved
–
–
–
–
–
–
–
–
(0xFE)
Reserved
–
–
–
–
–
–
–
–
(0xFD)
Reserved
–
–
–
–
–
–
–
–
(0xFC)
Reserved
–
–
–
–
–
–
–
–
(0xFB)
Reserved
–
–
–
–
–
–
–
–
(0xFA)
Reserved
–
–
–
–
–
–
–
–
(0xF9)
Reserved
–
–
–
–
–
–
–
–
(0xF8)
Reserved
–
–
–
–
–
–
–
–
(0xF7)
Reserved
–
–
–
–
–
–
–
–
(0xF6)
Reserved
–
–
–
–
–
–
–
–
(0xF5)
Reserved
–
–
–
–
–
–
–
–
(0xF4)
Reserved
–
–
–
–
–
–
–
–
(0xF3)
Reserved
–
–
–
–
–
–
–
–
(0xF2)
Reserved
–
–
–
–
–
–
–
–
(0xF1)
Reserved
–
–
–
–
–
–
–
–
(0xF0)
Reserved
–
–
–
–
–
–
–
–
(0xEF)
Reserved
–
–
–
–
–
–
–
–
(0xEE)
Reserved
–
–
–
–
–
–
–
–
(0xED)
Reserved
–
–
–
–
–
–
–
–
(0xEC)
Reserved
–
–
–
–
–
–
–
–
(0xEB)
Reserved
–
–
–
–
–
–
–
–
(0xEA)
Reserved
–
–
–
–
–
–
–
–
(0xE9)
Reserved
–
–
–
–
–
–
–
–
(0xE8)
Reserved
–
–
–
–
–
–
–
–
(0xE7)
Reserved
–
–
–
–
–
–
–
–
(0xE6)
Reserved
–
–
–
–
–
–
–
–
(0xE5)
Reserved
–
–
–
–
–
–
–
–
(0xE4)
Reserved
–
–
–
–
–
–
–
–
(0xE3)
Reserved
–
–
–
–
–
–
–
–
(0xE2)
Reserved
–
–
–
–
–
–
–
–
(0xE1)
Reserved
–
–
–
–
–
–
–
–
(0xE0)
Reserved
–
–
–
–
–
–
–
–
(0xDF)
Reserved
–
–
–
–
–
–
–
–
(0xDE)
Reserved
–
–
–
–
–
–
–
–
(0xDD)
Reserved
–
–
–
–
–
–
–
–
(0xDC)
Reserved
–
–
–
–
–
–
–
–
(0xDB)
Reserved
–
–
–
–
–
–
–
–
(0xDA)
Reserved
–
–
–
–
–
–
–
–
(0xD9)
Reserved
–
–
–
–
–
–
–
–
(0xD8)
Reserved
–
–
–
–
–
–
–
–
(0xD7)
Reserved
–
–
–
–
–
–
–
–
(0xD6)
Reserved
–
–
–
–
–
–
–
–
(0xD5)
Reserved
–
–
–
–
–
–
–
–
(0xD4)
Reserved
–
–
–
–
–
–
–
–
(0xD3)
Reserved
–
–
–
–
–
–
–
–
(0xD2)
Reserved
–
–
–
–
–
–
–
–
(0xD1)
Reserved
–
–
–
–
–
–
–
–
(0xD0)
Reserved
–
–
–
–
–
–
–
–
(0xCF)
Reserved
–
–
–
–
–
–
–
–
(0xCE)
Reserved
–
–
–
–
–
–
–
–
(0xCD)
Reserved
–
–
–
–
–
–
–
–
(0xCC)
Reserved
–
–
–
–
–
–
–
–
(0xCB)
Reserved
–
–
–
–
–
–
–
–
(0xCA)
Reserved
–
–
–
–
–
–
–
–
(0xC9)
Reserved
–
–
–
–
–
–
–
–
(0xC8)
Reserved
–
–
–
–
–
–
–
–
(0xC7)
Reserved
–
–
–
–
–
–
–
–
(0xC6)
UDR0
(0xC5)
UBRR0H
USART I/O Data Register
Page
189
USART Baud Rate Register High
193
(0xC4)
UBRR0L
(0xC3)
Reserved
–
–
–
USART Baud Rate Register Low
–
–
–
–
–
193
(0xC2)
UCSR0C
UMSEL01
UMSEL00
UPM01
UPM00
USBS0
UCSZ01 /UDORD0
UCSZ00 / UCPHA0
UCPOL0
191/206
8
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(0xC1)
UCSR0B
RXCIE0
TXCIE0
UDRIE0
RXEN0
TXEN0
UCSZ02
RXB80
TXB80
Page
190
(0xC0)
UCSR0A
RXC0
TXC0
UDRE0
FE0
DOR0
UPE0
U2X0
MPCM0
189
(0xBF)
Reserved
–
–
–
–
–
–
–
–
(0xBE)
Reserved
–
–
–
–
–
–
–
–
(0xBD)
TWAMR
TWAM6
TWAM5
TWAM4
TWAM3
TWAM2
TWAM1
TWAM0
–
239
(0xBC)
TWCR
TWINT
TWEA
TWSTA
TWSTO
TWWC
TWEN
–
TWIE
236
(0xBB)
TWDR
(0xBA)
TWAR
TWA6
TWA5
TWA4
TWS7
TWS6
TWS5
2-wire Serial Interface Data Register
(0xB9)
TWSR
(0xB8)
TWBR
(0xB7)
Reserved
–
(0xB6)
ASSR
–
(0xB5)
Reserved
–
238
TWA3
TWA2
TWA1
TWA0
TWGCE
239
TWS4
TWS3
–
TWPS1
TWPS0
238
2-wire Serial Interface Bit Rate Register
236
–
–
–
–
–
–
EXCLK
AS2
TCN2UB
OCR2AUB
OCR2BUB
TCR2AUB
TCR2BUB
–
–
–
–
–
–
–
158
(0xB4)
OCR2B
Timer/Counter2 Output Compare Register B
156
(0xB3)
OCR2A
Timer/Counter2 Output Compare Register A
156
(0xB2)
TCNT2
(0xB1)
TCCR2B
FOC2A
FOC2B
–
Timer/Counter2 (8-bit)
–
WGM22
CS22
CS21
CS20
156
155
(0xB0)
TCCR2A
COM2A1
COM2A0
COM2B1
COM2B0
–
–
WGM21
WGM20
152
(0xAF)
Reserved
–
–
–
–
–
–
–
–
(0xAE)
Reserved
–
–
–
–
–
–
–
–
(0xAD)
Reserved
–
–
–
–
–
–
–
–
(0xAC)
Reserved
–
–
–
–
–
–
–
–
(0xAB)
Reserved
–
–
–
–
–
–
–
–
(0xAA)
Reserved
–
–
–
–
–
–
–
–
(0xA9)
Reserved
–
–
–
–
–
–
–
–
(0xA8)
Reserved
–
–
–
–
–
–
–
–
(0xA7)
Reserved
–
–
–
–
–
–
–
–
(0xA6)
Reserved
–
–
–
–
–
–
–
–
(0xA5)
Reserved
–
–
–
–
–
–
–
–
(0xA4)
Reserved
–
–
–
–
–
–
–
–
(0xA3)
Reserved
–
–
–
–
–
–
–
–
(0xA2)
Reserved
–
–
–
–
–
–
–
–
(0xA1)
Reserved
–
–
–
–
–
–
–
–
(0xA0)
Reserved
–
–
–
–
–
–
–
–
(0x9F)
Reserved
–
–
–
–
–
–
–
–
(0x9E)
Reserved
–
–
–
–
–
–
–
–
(0x9D)
Reserved
–
–
–
–
–
–
–
–
(0x9C)
Reserved
–
–
–
–
–
–
–
–
(0x9B)
Reserved
–
–
–
–
–
–
–
–
(0x9A)
Reserved
–
–
–
–
–
–
–
–
(0x99)
Reserved
–
–
–
–
–
–
–
–
(0x98)
Reserved
–
–
–
–
–
–
–
–
(0x97)
Reserved
–
–
–
–
–
–
–
–
(0x96)
Reserved
–
–
–
–
–
–
–
–
(0x95)
Reserved
–
–
–
–
–
–
–
–
(0x94)
Reserved
–
–
–
–
–
–
–
–
(0x93)
Reserved
–
–
–
–
–
–
–
–
(0x92)
Reserved
–
–
–
–
–
–
–
–
(0x91)
Reserved
–
–
–
–
–
–
–
–
(0x90)
Reserved
–
–
–
–
–
–
–
–
(0x8F)
Reserved
–
–
–
–
–
–
–
–
(0x8E)
Reserved
–
–
–
–
–
–
–
–
(0x8D)
Reserved
–
–
–
–
–
–
–
–
(0x8C)
Reserved
–
–
–
–
–
–
–
–
(0x8B)
OCR1BH
Timer/Counter1 - Output Compare Register B High Byte
132
(0x8A)
OCR1BL
Timer/Counter1 - Output Compare Register B Low Byte
132
(0x89)
OCR1AH
Timer/Counter1 - Output Compare Register A High Byte
132
(0x88)
OCR1AL
Timer/Counter1 - Output Compare Register A Low Byte
132
(0x87)
ICR1H
Timer/Counter1 - Input Capture Register High Byte
133
(0x86)
ICR1L
Timer/Counter1 - Input Capture Register Low Byte
133
(0x85)
TCNT1H
Timer/Counter1 - Counter Register High Byte
132
(0x84)
TCNT1L
Timer/Counter1 - Counter Register Low Byte
132
(0x83)
Reserved
–
–
–
–
–
–
–
(0x82)
TCCR1C
FOC1A
FOC1B
–
–
–
–
–
–
(0x81)
TCCR1B
ICNC1
ICES1
–
WGM13
WGM12
CS12
CS11
CS10
130
(0x80)
TCCR1A
COM1A1
COM1A0
COM1B1
COM1B0
–
–
WGM11
WGM10
128
–
131
9
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(0x7F)
DIDR1
–
–
–
–
–
–
AIN1D
AIN0D
244
(0x7E)
DIDR0
–
–
ADC5D
ADC4D
ADC3D
ADC2D
ADC1D
ADC0D
261
(0x7D)
Reserved
–
–
–
–
–
–
–
–
(0x7C)
ADMUX
REFS1
REFS0
ADLAR
–
MUX3
MUX2
MUX1
MUX0
257
(0x7B)
ADCSRB
–
ACME
–
–
–
ADTS2
ADTS1
ADTS0
260
(0x7A)
ADCSRA
ADEN
ADSC
ADATE
ADIF
ADIE
ADPS2
ADPS1
ADPS0
(0x79)
ADCH
ADC Data Register High byte
Page
258
260
(0x78)
ADCL
(0x77)
Reserved
–
–
–
–
–
–
–
–
(0x76)
Reserved
–
–
–
–
–
–
–
–
(0x75)
Reserved
–
–
–
–
–
–
–
–
(0x74)
Reserved
–
–
–
–
–
–
–
–
(0x73)
Reserved
–
–
–
–
–
–
–
–
(0x72)
Reserved
–
–
–
–
–
–
–
–
(0x71)
Reserved
–
–
–
–
–
–
–
–
(0x70)
TIMSK2
–
–
–
–
–
OCIE2B
OCIE2A
TOIE2
157
(0x6F)
TIMSK1
–
–
ICIE1
–
–
OCIE1B
OCIE1A
TOIE1
133
(0x6E)
TIMSK0
–
–
–
–
–
OCIE0B
OCIE0A
TOIE0
105
(0x6D)
PCMSK2
PCINT23
PCINT22
PCINT21
PCINT20
PCINT19
PCINT18
PCINT17
PCINT16
68
(0x6C)
PCMSK1
–
PCINT14
PCINT13
PCINT12
PCINT11
PCINT10
PCINT9
PCINT8
68
(0x6B)
PCMSK0
PCINT7
PCINT6
PCINT5
PCINT4
PCINT3
PCINT2
PCINT1
PCINT0
68
(0x6A)
Reserved
–
–
–
–
–
–
–
–
(0x69)
EICRA
–
–
–
–
ISC11
ISC10
ISC01
ISC00
(0x68)
PCICR
–
–
–
–
–
PCIE2
PCIE1
PCIE0
(0x67)
Reserved
–
–
–
–
–
–
–
–
(0x66)
OSCCAL
(0x65)
Reserved
–
–
–
–
–
–
–
–
(0x64)
PRR
PRTWI
PRTIM2
PRTIM0
–
PRTIM1
PRSPI
PRUSART0
PRADC
(0x63)
Reserved
–
–
–
–
–
–
–
–
(0x62)
Reserved
–
–
–
–
–
–
–
–
(0x61)
CLKPR
CLKPCE
–
–
–
CLKPS3
CLKPS2
CLKPS1
CLKPS0
37
(0x60)
WDTCSR
WDIF
WDIE
WDP3
WDCE
WDE
WDP2
WDP1
WDP0
54
0x3F (0x5F)
SREG
I
T
H
S
V
N
Z
C
9
0x3E (0x5E)
SPH
–
–
–
–
–
(SP10) 5.
SP9
SP8
12
0x3D (0x5D)
SPL
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
12
0x3C (0x5C)
Reserved
–
–
–
–
–
–
–
–
0x3B (0x5B)
Reserved
–
–
–
–
–
–
–
–
0x3A (0x5A)
Reserved
–
–
–
–
–
–
–
–
0x39 (0x59)
Reserved
–
–
–
–
–
–
–
–
0x38 (0x58)
Reserved
–
–
–
–
–
–
–
–
0x37 (0x57)
SPMCSR
SPMIE
(RWWSB)5.
–
(RWWSRE)5.
BLBSET
PGWRT
PGERS
SELFPRGEN
0x36 (0x56)
Reserved
–
–
–
–
–
–
–
–
0x35 (0x55)
MCUCR
–
BODS
BODSE
PUD
–
–
IVSEL
IVCE
0x34 (0x54)
MCUSR
–
–
–
–
WDRF
BORF
EXTRF
PORF
54
0x33 (0x53)
SMCR
–
–
–
–
SM2
SM1
SM0
SE
40
0x32 (0x52)
Reserved
–
–
–
–
–
–
–
–
0x31 (0x51)
Reserved
–
–
–
–
–
–
–
–
0x30 (0x50)
ACSR
ACD
ACBG
ACO
ACI
ACIE
ACIC
ACIS1
ACIS0
0x2F (0x4F)
Reserved
–
–
–
–
–
–
–
–
0x2E (0x4E)
SPDR
0x2D (0x4D)
SPSR
SPIF
WCOL
–
–
–
–
–
SPI2X
168
0x2C (0x4C)
SPCR
SPIE
SPE
DORD
MSTR
CPOL
CPHA
SPR1
SPR0
167
0x2B (0x4B)
GPIOR2
General Purpose I/O Register 2
0x2A (0x4A)
GPIOR1
General Purpose I/O Register 1
0x29 (0x49)
Reserved
0x28 (0x48)
OCR0B
Timer/Counter0 Output Compare Register B
0x27 (0x47)
OCR0A
Timer/Counter0 Output Compare Register A
0x26 (0x46)
TCNT0
0x25 (0x45)
TCCR0B
FOC0A
FOC0B
–
–
WGM02
CS02
CS01
CS00
0x24 (0x44)
TCCR0A
COM0A1
COM0A0
COM0B1
COM0B0
–
–
WGM01
WGM00
0x23 (0x43)
GTCCR
TSM
–
–
–
–
–
PSRASY
PSRSYNC
0x22 (0x42)
EEARH
(EEPROM Address Register High Byte) 5.
0x21 (0x41)
EEARL
EEPROM Address Register Low Byte
21
0x20 (0x40)
EEDR
EEPROM Data Register
21
0x1F (0x3F)
EECR
0x1E (0x3E)
GPIOR0
ADC Data Register Low byte
260
Oscillator Calibration Register
37
SPI Data Register
–
–
–
–
65
42
284
44/62/86
242
169
25
25
–
–
–
–
Timer/Counter0 (8-bit)
–
–
EEPM1
EEPM0
EERIE
General Purpose I/O Register 0
137/159
21
EEMPE
EEPE
EERE
21
25
10
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0x1D (0x3D)
EIMSK
–
–
–
–
–
–
INT1
INT0
Page
66
0x1C (0x3C)
EIFR
–
–
–
–
–
–
INTF1
INTF0
66
0x1B (0x3B)
PCIFR
–
–
–
–
–
PCIF2
PCIF1
PCIF0
0x1A (0x3A)
Reserved
–
–
–
–
–
–
–
–
0x19 (0x39)
Reserved
–
–
–
–
–
–
–
–
0x18 (0x38)
Reserved
–
–
–
–
–
–
–
–
0x17 (0x37)
TIFR2
–
–
–
–
–
OCF2B
OCF2A
TOV2
157
0x16 (0x36)
TIFR1
–
–
ICF1
–
–
OCF1B
OCF1A
TOV1
134
0x15 (0x35)
TIFR0
–
–
–
–
–
OCF0B
OCF0A
TOV0
0x14 (0x34)
Reserved
–
–
–
–
–
–
–
–
0x13 (0x33)
Reserved
–
–
–
–
–
–
–
–
0x12 (0x32)
Reserved
–
–
–
–
–
–
–
–
0x11 (0x31)
Reserved
–
–
–
–
–
–
–
–
0x10 (0x30)
Reserved
–
–
–
–
–
–
–
–
0x0F (0x2F)
Reserved
–
–
–
–
–
–
–
–
0x0E (0x2E)
Reserved
–
–
–
–
–
–
–
–
0x0D (0x2D)
Reserved
–
–
–
–
–
–
–
–
0x0C (0x2C)
Reserved
–
–
–
–
–
–
–
–
0x0B (0x2B)
PORTD
PORTD7
PORTD6
PORTD5
PORTD4
PORTD3
PORTD2
PORTD1
PORTD0
87
0x0A (0x2A)
DDRD
DDD7
DDD6
DDD5
DDD4
DDD3
DDD2
DDD1
DDD0
87
0x09 (0x29)
PIND
PIND7
PIND6
PIND5
PIND4
PIND3
PIND2
PIND1
PIND0
87
0x08 (0x28)
PORTC
–
PORTC6
PORTC5
PORTC4
PORTC3
PORTC2
PORTC1
PORTC0
86
0x07 (0x27)
DDRC
–
DDC6
DDC5
DDC4
DDC3
DDC2
DDC1
DDC0
86
0x06 (0x26)
PINC
–
PINC6
PINC5
PINC4
PINC3
PINC2
PINC1
PINC0
86
0x05 (0x25)
PORTB
PORTB7
PORTB6
PORTB5
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
86
0x04 (0x24)
DDRB
DDB7
DDB6
DDB5
DDB4
DDB3
DDB2
DDB1
DDB0
86
0x03 (0x23)
PINB
PINB7
PINB6
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
86
0x02 (0x22)
Reserved
–
–
–
–
–
–
–
–
0x01 (0x21)
Reserved
–
–
–
–
–
–
–
–
0x0 (0x20)
Reserved
–
–
–
–
–
–
–
–
Note:
1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses
should never be written.
2. I/O Registers within the address range 0x00 - 0x1F are directly bit-accessible using the SBI and CBI instructions. In these
registers, the value of single bits can be checked by using the SBIS and SBIC instructions.
3. Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most other AVRs, the CBI and SBI
instructions will only operate on the specified bit, and can therefore be used on registers containing such Status Flags. The
CBI and SBI instructions work with registers 0x00 to 0x1F only.
4. When using the I/O specific commands IN and OUT, the I/O addresses 0x00 - 0x3F must be used. When addressing I/O
Registers as data space using LD and ST instructions, 0x20 must be added to these addresses. The
ATmega48PA/88PA/168PA/328P is a complex microcontroller with more peripheral units than can be supported within the 64
location reserved in Opcode for the IN and OUT instructions. For the Extended I/O space from 0x60 - 0xFF in SRAM, only
the ST/STS/STD and LD/LDS/LDD instructions can be used.
5. Only valid for ATmega88PA.
11
8161DS–AVR–10/09
ATmega48PA/88PA/168PA/328P
6. Instruction Set Summary
Mnemonics
Operands
Description
Operation
Flags
#Clocks
ARITHMETIC AND LOGIC INSTRUCTIONS
ADD
Rd, Rr
Add two Registers
Rd ← Rd + Rr
Z,C,N,V,H
ADC
Rd, Rr
Add with Carry two Registers
Rd ← Rd + Rr + C
Z,C,N,V,H
1
ADIW
Rdl,K
Add Immediate to Word
Rdh:Rdl ← Rdh:Rdl + K
Z,C,N,V,S
2
SUB
Rd, Rr
Subtract two Registers
Rd ← Rd - Rr
Z,C,N,V,H
1
SUBI
Rd, K
Subtract Constant from Register
Rd ← Rd - K
Z,C,N,V,H
1
SBC
Rd, Rr
Subtract with Carry two Registers
Rd ← Rd - Rr - C
Z,C,N,V,H
1
SBCI
Rd, K
Subtract with Carry Constant from Reg.
Rd ← Rd - K - C
Z,C,N,V,H
1
SBIW
Rdl,K
Subtract Immediate from Word
Rdh:Rdl ← Rdh:Rdl - K
Z,C,N,V,S
2
AND
Rd, Rr
Logical AND Registers
Rd ← Rd • Rr
Z,N,V
1
ANDI
Rd, K
Logical AND Register and Constant
Rd ← Rd • K
Z,N,V
1
OR
Rd, Rr
Logical OR Registers
Rd ← Rd v Rr
Z,N,V
1
ORI
Rd, K
Logical OR Register and Constant
Rd ← Rd v K
Z,N,V
1
EOR
Rd, Rr
Exclusive OR Registers
Rd ← Rd ⊕ Rr
Z,N,V
1
1
COM
Rd
One’s Complement
Rd ← 0xFF − Rd
Z,C,N,V
1
NEG
Rd
Two’s Complement
Rd ← 0x00 − Rd
Z,C,N,V,H
1
SBR
Rd,K
Set Bit(s) in Register
Rd ← Rd v K
Z,N,V
1
CBR
Rd,K
Clear Bit(s) in Register
Rd ← Rd • (0xFF - K)
Z,N,V
1
INC
Rd
Increment
Rd ← Rd + 1
Z,N,V
1
DEC
Rd
Decrement
Rd ← Rd − 1
Z,N,V
1
TST
Rd
Test for Zero or Minus
Rd ← Rd • Rd
Z,N,V
1
CLR
Rd
Clear Register
Rd ← Rd ⊕ Rd
Z,N,V
1
SER
Rd
Set Register
Rd ← 0xFF
None
1
MUL
Rd, Rr
Multiply Unsigned
R1:R0 ← Rd x Rr
Z,C
2
MULS
Rd, Rr
Multiply Signed
R1:R0 ← Rd x Rr
Z,C
2
MULSU
Rd, Rr
Multiply Signed with Unsigned
R1:R0 ← Rd x Rr
Z,C
2
FMUL
Rd, Rr
Fractional Multiply Unsigned
R1:R0 ← (Rd x Rr)