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
Non-volatile Program and Data Memories
– 4/8/16K Bytes of In-System Self-Programmable Flash (ATmega48/88/168)
Endurance: 10,000 Write/Erase Cycles
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– 256/512/512 Bytes EEPROM (ATmega48/88/168)
Endurance: 100,000 Write/Erase Cycles
– 512/1K/1K Byte Internal SRAM (ATmega48/88/168)
– 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
– 6-channel 10-bit ADC in PDIP Package
– Programmable Serial USART
– Master/Slave SPI Serial Interface
– Byte-oriented 2-wire Serial Interface
– 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
– Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, and
Standby
I/O and Packages
– 23 Programmable I/O Lines
– 28-pin PDIP, 32-lead TQFP and 32-pad QFN/MLF
Operating Voltage:
– 1.8 - 5.5V for ATmega48V/88V/168V
– 2.7 - 5.5V for ATmega48/88/168
Temperature Range:
– -40
°
C to 85
°
C
Speed Grade:
– ATmega48V/88V/168V: 0 - 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V
– ATmega48/88/168: 0 - 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V
•
•
8-bit
Microcontroller
with 8K Bytes
In-System
Programmable
Flash
ATmega48/V
ATmega88/V
ATmega168/V
Preliminary
•
•
•
•
•
Rev. 2545E–AVR–02/05
•
Low Power Consumption
– Active Mode:
1 MHz, 1.8V: 240µA
32 kHz, 1.8V: 15µA (including Oscillator)
– Power-down Mode:
0.1µA at 1.8V
1. Pin Configurations
Figure 1-1.
Pinout ATmega48/88/168
PDIP
(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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
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)
TQFP Top View
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)
MLF Top View
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)
32
31
30
29
28
27
26
25
32
31
30
29
28
27
26
25
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
24
23
22
21
20
19
18
17
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
ADC7
GND
AREF
ADC6
AVCC
PB5 (SCK/PCINT5)
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
24
23
22
21
20
19
18
17
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
NOTE: Bottom pad should be soldered to ground.
2
ATmega48/88/168
2545E–AVR–02/05
(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
ATmega48/88/168
1.1
Disclaimer
Typical values contained in this datasheet are based on simulations and characterization of
other AVR microcontrollers manufactured on the same process technology. Min and Max values
will be available after the device is characterized.
2. Overview
The ATmega48/88/168 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
ATmega48/88/168 achieves throughputs approaching 1 MIPS per MHz allowing the system
designer to optimize power consumption versus processing speed.
2.1
Block Diagram
Figure 2-1.
Block Diagram
GND
VCC
Watchdog
Timer
Watchdog
Oscillator
Power
Supervision
POR / BOD &
RESET
debugWIRE
PROGRAM
LOGIC
Oscillator
Circuits /
Clock
Generation
Flash
SRAM
CPU
EEPROM
AVCC
AREF
GND
8bit T/C 0
16bit T/C 1
A/D Conv.
2
DATABUS
8bit T/C 2
Analog
Comp.
Internal
Bandgap
6
USART 0
SPI
TWI
PORT D (8)
PORT B (8)
PORT C (7)
RESET
XTAL[1..2]
PD[0..7]
PB[0..7]
PC[0..6]
ADC[6..7]
3
2545E–AVR–02/05
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
architecture is more code efficient while achieving throughputs up to ten times faster than con-
ventional CISC microcontrollers.
The ATmega48/88/168 provides the following features: 4K/8K/16K bytes of In-System Program-
mable Flash with Read-While-Write capabilities, 256/512/512 bytes EEPROM, 512/1K/1K 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 inter-
rupt 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 dur-
ing 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 pro-
gram 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 ATmega48/88/168 is a powerful microcontroller that provides a highly
flexible and cost effective solution to many embedded control applications.
The ATmega48/88/168 AVR is supported with a full suite of program and system development
tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators, In-Circuit Emu-
lators, and Evaluation kits.
2.2
Comparison Between ATmega48, ATmega88, and ATmega168
The ATmega48, ATmega88 and ATmega168 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.
Device
ATmega48
ATmega88
ATmega168
Memory Size Summary
Flash
4K Bytes
8K Bytes
16K Bytes
EEPROM
256 Bytes
512 Bytes
512 Bytes
RAM
512 Bytes
1K Bytes
1K Bytes
Interrupt Vector Size
1 instruction word/vector
1 instruction word/vector
2 instruction words/vector
ATmega88 and ATmega168 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.
4
ATmega48/88/168
2545E–AVR–02/05
ATmega48/88/168
In ATmega48, there is no Read-While-Write support and no separate Boot Loader Section. The
SPM instruction can execute from the entire Flash.
2.3
2.3.1
Pin Descriptions
VCC
Digital supply voltage.
2.3.2
GND
Ground.
2.3.3
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 Oscil-
lator 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
71
and
”System Clock and Clock Options” on page 25.
2.3.4
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.
2.3.5
PC6/RESET
If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the electrical char-
acteristics 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 8-1 on page 44.
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
75.
2.3.6
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
5
2545E–AVR–02/05
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