2545DS–AVR–07/04
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 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 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
•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
8-bit
Microcontroller
with 8K Bytes
In-System
Programmable
Flash
ATmega48/V
ATmega88/V
ATmega168/V
Preliminary
Summary
Note: This is a summary document. A complete document
is available on our Web site at www.atmel.com.
2ATmega48/88/168
2545DS–AVR–07/04
Pin Configurations
Figure 1. Pinout ATmega48/88/168
Disclaimer Typical values contained in this datasheet are based on simulations and characteriza-
tion of other AVR microcontrollers manufactured on the same process technology. Min
and Max values will be available after the device is characterized.
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
ADC7
GND
AREF
ADC6
AVCC
PB5 (SCK/PCINT5)
32
31
30
29
28
27
26
25
9
10
11
12
13
14
15
16
(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
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
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
(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
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)
PDIP
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
32
31
30
29
28
27
26
25
9
10
11
12
13
14
15
16
MLF Top View
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
GND
VCC
GND
VCC
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
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
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)
NOTE: Bottom pad should be soldered to ground.
3
ATmega48/88/168
2545DS–AVR–07/04
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.
Block Diagram Figure 2. Block Diagram
PORT C (7)PORT B (8)PORT D (8)
USART 0
8bit T/C 2
16bit T/C 18bit T/C 0 A/D Conv.
Internal
Bandgap
Analog
Comp.
SPI TWI
SRAMFlash
EEPROM
Watchdog
Oscillator
Watchdog
Timer
Oscillator
Circuits /
Clock
Generation
Power
Supervision
POR / BOD &
RESET
VCC
GND
PROGRAM
LOGIC
debugWIRE
2
GND
AREF
AVCC
DATA B U S
ADC[6..7]PC[0..6]PB[0..7]PD[0..7]
6
RESET
XTAL[1..2]
CPU
4ATmega48/88/168
2545DS–AVR–07/04
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 conventional CISC microcontrollers.
The ATmega48/88/168 provides the following features: 4K/8K/16K bytes of In-System
Programmable 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 reg-
isters, 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 MLF packages), a pro-
grammable 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. Soft-
ware 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 devel-
opment tools including: C Compilers, Macro Assemblers, Program
Debugger/Simulators, In-Circuit Emulators, and Evaluation kits.
Comparison Between
ATmega48, ATmega88,
and ATmega168
The ATmega48, ATmega88 and ATmega168 differ only in memory sizes, boot loader
support, and interrupt vector sizes. Table 1 summarizes the different memory and inter-
rupt vector sizes for the three devices.
ATmega88 and ATmega168 support a real Read-While-Write Self-Programming mech-
anism. There is a separate Boot Loader Section, and the SPM instruction can only
execute from there. In ATmega48, there is no Read-While-Write support and no sepa-
rate Boot Loader Section. The SPM instruction can execute from the entire Flash.
Table 1. Memory Size Summary
Device Flash EEPROM RAM Interrupt Vector Size
ATmega48 4K Bytes 256 Bytes 512 Bytes 1 instruction word/vector
ATmega88 8K Bytes 512 Bytes 1K Bytes 1 instruction word/vector
ATmega168 16K Bytes 512 Bytes 1K Bytes 2 instruction words/vector
5
ATmega48/88/168
2545DS–AVR–07/04
Pin Descriptions
VCC Digital supply voltage.
GND Ground.
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 invert-
ing 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 69 and “System Clock and Clock Options” on page 24.
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.
PC6/RESET If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the electri-
cal 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 20 on page 41. 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 73.
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.
The various special features of Port D are elaborated in “Alternate Functions of Port D”
on page 75.
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.
AREF AREF is the analog reference pin for the A/D Converter.
6ATmega48/88/168
2545DS–AVR–07/04
ADC7..6
(TQFP and MLF Package Only)
In the TQFP and 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.
7
ATmega48/88/168
2545DS–AVR–07/04
Register Summary
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
(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 USART I/O Data Register 180
(0xC5) UBRR0H USART Baud Rate Register High 184
(0xC4) UBRR0L USART Baud Rate Register Low 184
(0xC3) Reserved – – – – – – – –
(0xC2) UCSR0C UMSEL01 UMSEL00 UPM01 UPM00 USBS0 UCSZ01 /UDORD0 UCSZ00 / UCPHA0 UCPOL0 183/196
(0xC1) UCSR0B RXCIE0 TXCIE0 UDRIE0 RXEN0 TXEN0 UCSZ02 RXB80 TXB80 182
(0xC0) UCSR0A RXC0 TXC0 UDRE0 FE0 DOR0 UPE0 U2X0 MPCM0 180
8ATmega48/88/168
2545DS–AVR–07/04
(0xBF) Reserved – – – – – – – –
(0xBE) Reserved – – – – – – – –
(0xBD) TWAMR TWAM6 TWAM5 TWAM4 TWAM3 TWAM2 TWAM1 TWAM0 –209
(0xBC) TWCR TWINT TWEA TWSTA TWSTO TWWC TWEN –TWIE 206
(0xBB) TWDR 2-wire Serial Interface Data Register 208
(0xBA) TWAR TWA6 TWA5 TWA4 TWA3 TWA2 TWA1 TWA0 TWGCE 208
(0xB9) TWSR TWS7 TWS6 TWS5 TWS4 TWS3 –TWPS1TWPS0 207
(0xB8) TWBR 2-wire Serial Interface Bit Rate Register 206
(0xB7) Reserved – – – – – – –
(0xB6) ASSR – EXCLK AS2 TCN2UB OCR2AUB OCR2BUB TCR2AUB TCR2BUB 150
(0xB5) Reserved – – – – – – – –
(0xB4) OCR2B Timer/Counter2 Output Compare Register B 147
(0xB3) OCR2A Timer/Counter2 Output Compare Register A 147
(0xB2) TCNT2 Timer/Counter2 (8-bit) 147
(0xB1) TCCR2B FOC2A FOC2B –– WGM22 CS22 CS21 CS20 146
(0xB0) TCCR2A COM2A1 COM2A0 COM2B1 COM2B0 ––WGM21WGM20 143
(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 129
(0x8A) OCR1BL Timer/Counter1 - Output Compare Register B Low Byte 129
(0x89) OCR1AH Timer/Counter1 - Output Compare Register A High Byte 129
(0x88) OCR1AL Timer/Counter1 - Output Compare Register A Low Byte 129
(0x87) ICR1H Timer/Counter1 - Input Capture Register High Byte 129
(0x86) ICR1L Timer/Counter1 - Input Capture Register Low Byte 129
(0x85) TCNT1H Timer/Counter1 - Counter Register High Byte 129
(0x84) TCNT1L Timer/Counter1 - Counter Register Low Byte 129
(0x83) Reserved – – – – – – – –
(0x82) TCCR1C FOC1A FOC1B – – – – – –128
(0x81) TCCR1B ICNC1 ICES1 – WGM13 WGM12 CS12 CS11 CS10 127
(0x80) TCCR1A COM1A1 COM1A0 COM1B1 COM1B0 ––WGM11WGM10 125
(0x7F) DIDR1 – – – – – –AIN1DAIN0D 230
(0x7E) DIDR0 –– ADC5D ADC4D ADC3D ADC2D ADC1D ADC0D 245
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
9
ATmega48/88/168
2545DS–AVR–07/04
(0x7D) Reserved – – – – – – – –
(0x7C) ADMUX REFS1 REFS0 ADLAR – MUX3 MUX2 MUX1 MUX0 241
(0x7B) ADCSRB –ACME – – – ADTS2 ADTS1 ADTS0 244
(0x7A) ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 242
(0x79) ADCH ADC Data Register High byte 244
(0x78) ADCL ADC Data Register Low byte 244
(0x77) Reserved – – – – – – – –
(0x76) Reserved – – – – – – – –
(0x75) Reserved – – – – – – – –
(0x74) Reserved – – – – – – – –
(0x73) Reserved – – – – – – – –
(0x72) Reserved – – – – – – – –
(0x71) Reserved – – – – – – – –
(0x70) TIMSK2 – – – – – OCIE2B OCIE2A TOIE2 148
(0x6F) TIMSK1 ––ICIE1 –– OCIE1B OCIE1A TOIE1 130
(0x6E) TIMSK0 – – – – – OCIE0B OCIE0A TOIE0 100
(0x6D) PCMSK2 PCINT23 PCINT22 PCINT21 PCINT20 PCINT19 PCINT18 PCINT17 PCINT16 83
(0x6C) PCMSK1 – PCINT14 PCINT13 PCINT12 PCINT11 PCINT10 PCINT9 PCINT8 83
(0x6B) PCMSK0 PCINT7 PCINT6 PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 84
(0x6A) Reserved – – – – – – – –
(0x69) EICRA – – – –ISC11ISC10ISC01ISC00 80
(0x68) PCICR – – – – – PCIE2 PCIE1 PCIE0
(0x67) Reserved – – – – – – – –
(0x66) OSCCAL Oscillator Calibration Register 30
(0x65) Reserved – – – – – – – –
(0x64) PRR PRTWI PRTIM2 PRTIM0 – PRTIM1 PRSPI PRUSART0 PRADC 37
(0x63) Reserved – – – – – – – –
(0x62) Reserved – – – – – – – –
(0x61) CLKPR CLKPCE – – – CLKPS3 CLKPS2 CLKPS1 CLKPS0 33
(0x60) WDTCSR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0 49
0x3F (0x5F) SREG I T H S V N Z C 9
0x3E (0x5E) SPH – – – – – (SP10) 5. SP9 SP8 11
0x3D (0x5D) SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 11
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 260
0x36 (0x56) Reserved – – – – – – – –
0x35 (0x55) MCUCR – – –PUD–– IVSEL IVCE
0x34 (0x54) MCUSR – – – – WDRF BORF EXTRF PORF
0x33 (0x53) SMCR – – – –SM2SM1SM0SE 35
0x32 (0x52) Reserved – – – – – – – –
0x31 (0x51) Reserved – – – – – – – –
0x30 (0x50) ACSR ACD ACBG ACO ACI ACIE ACIC ACIS1 ACIS0 228
0x2F (0x4F) Reserved – – – – – – – –
0x2E (0x4E) SPDR SPI Data Register 160
0x2D (0x4D) SPSR SPIF WCOL – – – – – SPI2X 160
0x2C (0x4C) SPCR SPIE SPE DORD MSTR CPOL CPHA SPR1 SPR0 158
0x2B (0x4B) GPIOR2 General Purpose I/O Register 2 23
0x2A (0x4A) GPIOR1 General Purpose I/O Register 1 23
0x29 (0x49) Reserved – – – – – – – –
0x28 (0x48) OCR0B Timer/Counter0 Output Compare Register B
0x27 (0x47) OCR0A Timer/Counter0 Output Compare Register A
0x26 (0x46) TCNT0 Timer/Counter0 (8-bit)
0x25 (0x45) TCCR0B FOC0A FOC0B –– WGM02 CS02 CS01 CS00
0x24 (0x44) TCCR0A COM0A1 COM0A0 COM0B1 COM0B0 ––WGM01WGM00
0x23 (0x43) GTCCR TSM – – – – – PSRASY PSRSYNC 103/152
0x22 (0x42) EEARH (EEPROM Address Register High Byte) 5. 18
0x21 (0x41) EEARL EEPROM Address Register Low Byte 18
0x20 (0x40) EEDR EEPROM Data Register 18
0x1F (0x3F) EECR –– EEPM1 EEPM0 EERIE EEMPE EEPE EERE 18
0x1E (0x3E) GPIOR0 General Purpose I/O Register 0 23
0x1D (0x3D) EIMSK – – – – – –INT1INT0 81
0x1C (0x3C) EIFR – – – – – – INTF1 INTF0 82
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
10 ATmega48/88/168
2545DS–AVR–07/04
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 ATmega48/88/168 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 ATmega88/168.
0x1B (0x3B) PCIFR – – – – – PCIF2 PCIF1 PCIF0
0x1A (0x3A) Reserved – – – – – – – –
0x19 (0x39) Reserved – – – – – – – –
0x18 (0x38) Reserved – – – – – – – –
0x17 (0x37) TIFR2 – – – – – OCF2B OCF2A TOV2 148
0x16 (0x36) TIFR1 ––ICF1 –– OCF1B OCF1A TOV1 130
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 79
0x0A (0x2A) DDRD DDD7 DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0 79
0x09 (0x29) PIND PIND7 PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0 79
0x08 (0x28) PORTC – PORTC6 PORTC5 PORTC4 PORTC3 PORTC2 PORTC1 PORTC0 79
0x07 (0x27) DDRC – DDC6 DDC5 DDC4 DDC3 DDC2 DDC1 DDC0 79
0x06 (0x26) PINC – PINC6 PINC5 PINC4 PINC3 PINC2 PINC1 PINC0 79
0x05 (0x25) PORTB PORTB7 PORTB6 PORTB5 PORTB4 PORTB3 PORTB2 PORTB1 PORTB0 79
0x04 (0x24) DDRB DDB7 DDB6 DDB5 DDB4 DDB3 DDB2 DDB1 DDB0 79
0x03 (0x23) PINB PINB7 PINB6 PINB5 PINB4 PINB3 PINB2 PINB1 PINB0 79
0x02 (0x22) Reserved – – – – – – – –
0x01 (0x21) Reserved – – – – – – – –
0x0 (0x20) Reserved – – – – – – – –
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
11
ATmega48/88/168
2545DS–AVR–07/04
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 1
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
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) << 1 Z,C 2
FMULS Rd, Rr Fractional Multiply Signed R1:R0 ← (Rd x Rr) << 1 Z,C 2
FMULSU Rd, Rr Fractional Multiply Signed with Unsigned R1:R0 ← (Rd x Rr) << 1 Z,C 2
BRANCH INSTRUCTIONS
RJMP k Relative Jump PC ← PC + k + 1 None 2
IJMP Indirect Jump to (Z) PC ← Z None 2
JMP(1) k Direct Jump PC ← kNone3
RCALL k Relative Subroutine Call PC ← PC + k + 1 None 3
ICALL Indirect Call to (Z) PC ← ZNone3
CALL(1) k Direct Subroutine Call PC ← kNone4
RET Subroutine Return PC ← STACK None 4
RETI Interrupt Return PC ← STACK I 4
CPSE Rd,Rr Compare, Skip if Equal if (Rd = Rr) PC ← PC + 2 or 3 None 1/2/3
CP Rd,Rr Compare Rd − Rr Z, N,V,C,H 1
CPC Rd,Rr Compare with Carry Rd − Rr − C Z, N,V,C,H 1
CPI Rd,K Compare Register with Immediate Rd − K Z, N,V,C,H 1
SBRC Rr, b Skip if Bit in Register Cleared if (Rr(b)=0) PC ← PC + 2 or 3 None 1/2/3
SBRS Rr, b Skip if Bit in Register is Set if (Rr(b)=1) PC ← PC + 2 or 3 None 1/2/3
SBIC P, b Skip if Bit in I/O Register Cleared if (P(b)=0) PC ← PC + 2 or 3 None 1/2/3
SBIS P, b Skip if Bit in I/O Register is Set if (P(b)=1) PC ← PC + 2 or 3 None 1/2/3
BRBS s, k Branch if Status Flag Set if (SREG(s) = 1) then PC←PC+k + 1 None 1/2
BRBC s, k Branch if Status Flag Cleared if (SREG(s) = 0) then PC←PC+k + 1 None 1/2
BREQ k Branch if Equal if (Z = 1) then PC ← PC + k + 1 None 1/2
BRNE k Branch if Not Equal if (Z = 0) then PC ← PC + k + 1 None 1/2
BRCS k Branch if Carry Set if (C = 1) then PC ← PC + k + 1 None 1/2
BRCC k Branch if Carry Cleared if (C = 0) then PC ← PC + k + 1 None 1/2
BRSH k Branch if Same or Higher if (C = 0) then PC ← PC + k + 1 None 1/2
BRLO k Branch if Lower if (C = 1) then PC ← PC + k + 1 None 1/2
BRMI k Branch if Minus if (N = 1) then PC ← PC + k + 1 None 1/2
BRPL k Branch if Plus if (N = 0) then PC ← PC + k + 1 None 1/2
BRGE k Branch if Greater or Equal, Signed if (N ⊕ V= 0) then PC ← PC + k + 1 None 1/2
BRLT k Branch if Less Than Zero, Signed if (N ⊕ V= 1) then PC ← PC + k + 1 None 1/2
BRHS k Branch if Half Carry Flag Set if (H = 1) then PC ← PC + k + 1 None 1/2
BRHC k Branch if Half Carry Flag Cleared if (H = 0) then PC ← PC + k + 1 None 1/2
BRTS k Branch if T Flag Set if (T = 1) then PC ← PC + k + 1 None 1/2
BRTC k Branch if T Flag Cleared if (T = 0) then PC ← PC + k + 1 None 1/2
BRVS k Branch if Overflow Flag is Set if (V = 1) then PC ← PC + k + 1 None 1/2
BRVC k Branch if Overflow Flag is Cleared if (V = 0) then PC ← PC + k + 1 None 1/2
12 ATmega48/88/168
2545DS–AVR–07/04
BRIE k Branch if Interrupt Enabled if ( I = 1) then PC ← PC + k + 1 None 1/2
BRID k Branch if Interrupt Disabled if ( I = 0) then PC ← PC + k + 1 None 1/2
BIT AND BIT-TEST INSTRUCTIONS
SBI P,b Set Bit in I/O Register I/O(P,b) ← 1None2
CBI P,b Clear Bit in I/O Register I/O(P,b) ← 0None2
LSL Rd Logical Shift Left Rd(n+1) ← Rd(n), Rd(0) ← 0 Z,C,N,V 1
LSR Rd Logical Shift Right Rd(n) ← Rd(n+1), Rd(7) ← 0 Z,C,N,V 1
ROL Rd Rotate Left Through Carry Rd(0)←C,Rd(n+1)← Rd(n),C←Rd(7) Z,C,N,V 1
ROR Rd Rotate Right Through Carry Rd(7)←C,Rd(n)← Rd(n+1),C←Rd(0) Z,C,N,V 1
ASR Rd Arithmetic Shift Right Rd(n) ← Rd(n+1), n=0..6 Z,C,N,V 1
SWAP Rd Swap Nibbles Rd(3..0)←Rd(7..4),Rd(7..4)←Rd(3..0) None 1
BSET s Flag Set SREG(s) ← 1 SREG(s) 1
BCLR s Flag Clear SREG(s) ← 0 SREG(s) 1
BST Rr, b Bit Store from Register to T T ← Rr(b) T 1
BLD Rd, b Bit load from T to Register Rd(b) ← TNone1
SEC Set Carry C ← 1C1
CLC Clear Carry C ← 0 C 1
SEN Set Negative Flag N ← 1N1
CLN Clear Negative Flag N ← 0 N 1
SEZ Set Zero Flag Z ← 1Z1
CLZ Clear Zero Flag Z ← 0 Z 1
SEI Global Interrupt Enable I ← 1I1
CLI Global Interrupt Disable I ← 0 I 1
SES Set Signed Test Flag S ← 1S1
CLS Clear Signed Test Flag S ← 0 S 1
SEV Set Twos Complement Overflow. V ← 1V1
CLV Clear Twos Complement Overflow V ← 0 V 1
SET Set T in SREG T ← 1T1
CLT Clear T in SREG T ← 0 T 1
SEH Set Half Carry Flag in SREG H ← 1H1
CLH Clear Half Carry Flag in SREG H ← 0 H 1
DATA TRANSFER INSTRUCTIONS
MOV Rd, Rr Move Between Registers Rd ← Rr None 1
MOVW Rd, Rr Copy Register Word Rd+1:Rd ← Rr+1:Rr None 1
LDI Rd, K Load Immediate Rd ← KNone1
LD Rd, X Load Indirect Rd ← (X) None 2
LD Rd, X+ Load Indirect and Post-Inc. Rd ← (X), X ← X + 1 None 2
LD Rd, - X Load Indirect and Pre-Dec. X ← X - 1, Rd ← (X) None 2
LD Rd, Y Load Indirect Rd ← (Y) None 2
LD Rd, Y+ Load Indirect and Post-Inc. Rd ← (Y), Y ← Y + 1 None 2
LD Rd, - Y Load Indirect and Pre-Dec. Y ← Y - 1, Rd ← (Y) None 2
LDD Rd,Y+q Load Indirect with Displacement Rd ← (Y + q) None 2
LD Rd, Z Load Indirect Rd ← (Z) None 2
LD Rd, Z+ Load Indirect and Post-Inc. Rd ← (Z), Z ← Z+1 None 2
LD Rd, -Z Load Indirect and Pre-Dec. Z ← Z - 1, Rd ← (Z) None 2
LDD Rd, Z+q Load Indirect with Displacement Rd ← (Z + q) None 2
LDS Rd, k Load Direct from SRAM Rd ← (k) None 2
ST X, Rr Store Indirect (X) ← Rr None 2
ST X+, Rr Store Indirect and Post-Inc. (X) ← Rr, X ← X + 1 None 2
ST - X, Rr Store Indirect and Pre-Dec. X ← X - 1, (X) ← Rr None 2
ST Y, Rr Store Indirect (Y) ← Rr None 2
ST Y+, Rr Store Indirect and Post-Inc. (Y) ← Rr, Y ← Y + 1 None 2
ST - Y, Rr Store Indirect and Pre-Dec. Y ← Y - 1, (Y) ← Rr None 2
STD Y+q,Rr Store Indirect with Displacement (Y + q) ← Rr None 2
ST Z, Rr Store Indirect (Z) ← Rr None 2
ST Z+, Rr Store Indirect and Post-Inc. (Z) ← Rr, Z ← Z + 1 None 2
ST -Z, Rr Store Indirect and Pre-Dec. Z ← Z - 1, (Z) ← Rr None 2
STD Z+q,Rr Store Indirect with Displacement (Z + q) ← Rr None 2
STS k, Rr Store Direct to SRAM (k) ← Rr None 2
LPM Load Program Memory R0 ← (Z) None 3
LPM Rd, Z Load Program Memory Rd ← (Z) None 3
LPM Rd, Z+ Load Program Memory and Post-Inc Rd ← (Z), Z ← Z+1 None 3
SPM Store Program Memory (Z) ← R1:R0 None -
IN Rd, P In Port Rd ← PNone1
OUT P, Rr Out Port P ← Rr None 1
PUSH Rr Push Register on Stack STACK ← Rr None 2
Mnemonics Operands Description Operation Flags #Clocks
13
ATmega48/88/168
2545DS–AVR–07/04
Note: 1. These instructions are only available in ATmega168.
POP Rd Pop Register from Stack Rd ← STACK None 2
MCU CONTROL INSTRUCTIONS
NOP No Operation None 1
SLEEP Sleep (see specific descr. for Sleep function) None 1
WDR Watchdog Reset (see specific descr. for WDR/timer) None 1
BREAK Break For On-chip Debug Only None N/A
Mnemonics Operands Description Operation Flags #Clocks
14 ATmega48/88/168
2545DS–AVR–07/04
Ordering Information
ATmega48
Note: 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information
and minimum quantities.
2. Pb-free packaging alternative
3. See Figure 131 on page 293 and Figure 132 on page 293.
Speed (MHz) Power Supply Ordering Code Package Operation Range
10(3) 1.8 - 5.5
ATmega48V-10AI
ATmega48V-10PI
ATmega48V-10MI
ATmega48V-10AJ(2)
ATmega48V-10PJ(2)
ATmega48V-10MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
20(3) 2.7 - 5.5
ATmega48-20AI
ATmega48-20PI
ATmega48-20MI
ATmega48-20AJ(2)
ATmega48-20PJ(2)
ATmega48-20MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
Package Type
32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP)
28P3 28-lead, 0.300” Wide, Plastic Dual Inline Package (PDIP)
32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF)
15
ATmega48/88/168
2545DS–AVR–07/04
ATmega88
Note: 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information
and minimum quantities.
2. Pb-free packaging alternative
3. See Figure 131 on page 293 and Figure 132 on page 293.
Speed (MHz) Power Supply Ordering Code Package Operation Range
10(3) 1.8 - 5.5
ATmega88V-10AI
ATmega88V-10PI
ATmega88V-10MI
ATmega88V-10AJ(2)
ATmega88V-10PJ(2)
ATmega88V-10MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
20(3) 2.7 - 5.5
ATmega88-20AI
ATmega88-20PI
ATmega88-20MI
ATmega88-20AJ(2)
ATmega88-20PJ(2)
ATmega88-20MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
Package Type
32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP)
28P3 28-lead, 0.300” Wide, Plastic Dual Inline Package (PDIP)
32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF)
16 ATmega48/88/168
2545DS–AVR–07/04
ATmega168
Note: 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information
and minimum quantities.
2. Pb-free packaging alternative
3. See Figure 131 on page 293 and Figure 132 on page 293.
Speed (MHz) Power Supply Ordering Code Package Operation Range
10(3) 1.8 - 5.5
ATmega168V-10AI
ATmega168V-10PI
ATmega168V-10MI
ATmega168V-10AJ(2)
ATmega168V-10PJ(2)
ATmega168V-10MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
20(3) 2.7 - 5.5
ATmega168-20AI
ATmega168-20PI
ATmega168-20MI
ATmega168-20AJ(2)
ATmega168-20PJ(2)
ATmega168-20MJ(2)
32A
28P3
32M1-A
32A
28P3
32M1-A
Industrial
(-40°C to 85°C)
Package Type
32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP)
28P3 28-lead, 0.300” Wide, Plastic Dual Inline Package (PDIP)
32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF)
17
ATmega48/88/168
2545DS–AVR–07/04
Packaging Information
32A
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
32A, 32-lead, 7 x 7 mm Body Size, 1.0 mm Body Thickness,
0.8 mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP) B
32A
10/5/2001
PIN 1 IDENTIFIER
0˚~7˚
PIN 1
L
C
A1 A2 A
D1
D
eE1 E
B
Notes: 1. This package conforms to JEDEC reference MS-026, Variation ABA.
2. Dimensions D1 and E1 do not include mold protrusion. Allowable
protrusion is 0.25 mm per side. Dimensions D1 and E1 are maximum
plastic body size dimensions including mold mismatch.
3. Lead coplanarity is 0.10 mm maximum.
A – – 1.20
A1 0.05 – 0.15
A2 0.95 1.00 1.05
D 8.75 9.00 9.25
D1 6.90 7.00 7.10 Note 2
E 8.75 9.00 9.25
E1 6.90 7.00 7.10 Note 2
B 0.30 – 0.45
C 0.09 – 0.20
L 0.45 – 0.75
e 0.80 TYP
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
18 ATmega48/88/168
2545DS–AVR–07/04
28P3
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28P3, 28-lead (0.300"/7.62 mm Wide) Plastic Dual
Inline Package (PDIP) B
28P3
09/28/01
PIN
1
E1
A1
B
REF
E
B1
C
L
SEATING PLANE
A
0º ~ 15º
D
e
eB
B2
(4 PLACES)
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A – – 4.5724
A1 0.508 – –
D 34.544 – 34.798 Note 1
E 7.620 – 8.255
E1 7.112 – 7.493 Note 1
B 0.381 – 0.533
B1 1.143 – 1.397
B2 0.762 – 1.143
L 3.175 – 3.429
C 0.203 – 0.356
eB – – 10.160
e 2.540 TYP
Note: 1. Dimensions D and E1 do not include mold Flash or Protrusion.
Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
19
ATmega48/88/168
2545DS–AVR–07/04
32M1-A
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
32M1-A, 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm
Micro Lead Frame Package (MLF) C
32M1-A
01/15/03
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Pin 1 ID
D1
D
E1 E
e
b
A3
A2
A1
A
D2
E2
0.08 C
L
1
2
3
P
P
0
1
2
3
A 0.80 0.90 1.00
A1 – 0.02 0.05
A2 – 0.65 1.00
A3 0.20 REF
b 0.18 0.23 0.30
D 5.00 BSC
D1 4.75 BSC
D2 2.95 3.10 3.25
E 5.00 BSC
E1 4.75BSC
E2 2.95 3.10 3.25
e 0.50 BSC
L 0.30 0.40 0.50
P – – 0.60
– – 12o
Notes: 1. JEDEC Standard MO-220, Fig. 2 (Anvil Singulation), VHHD-2.
TOP VIEW
SIDE VIEW
BOTTOM VIEW
0
Pin 1 ID
20 ATmega48/88/168
2545DS–AVR–07/04
Errata ATmega48 The revision letter in this section refers to the revision of the ATmega48 device.
Rev A •Wrong values read after Erase Only operation
•Watchdog Timer Interrupt disabled
•Start-up time with Crystal Oscillator is higher than expected
•High Power Consumption in Power-down with External Clock
•Asynchronous Oscillator does not stop in Power-down
1. Wrong values read after Erase Only operation
At supply voltages below 2.7 V, an EEPROM location that is erased by the Erase
Only operation may read as programmed (0x00).
Problem Fix/Workaround
If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write
operation with 0xFF as data in order to erase a location. In any case, the Write Only
operation can be used as intended. Thus no special considerations are needed as
long as the erased location is not read before it is programmed.
2. Watchdog Timer Interrupt disabled
If the watchdog timer interrupt flag is not cleared before a new timeout occurs, the
watchdog will be disabled, and the interrupt flag will automatically be cleared. This is
only applicable in interrupt only mode. If the Watchdog is configured to reset the
device in the watchdog time-out following an interrupt, the device works correctly.
Problem fix / Workaround
Make sure there is enough time to always service the first timeout event before a
new watchdog timeout occurs. This is done by selecting a long enough time-out
period.
3. Start-up time with Crystal Oscillator is higher than expected
The clock counting part of the start-up time is about 2 times higher than expected for
all start-up periods when running on an external Crystal. This applies only when
waking up by reset. Wake-up from power down is not affected. For most settings,
the clock counting parts is a small fraction of the overall start-up time, and thus, the
problem can be ignored. The exception is when using a very low frequency crystal
like for instance a 32 kHz clock crystal.
Problem fix / Workaround
No known workaround.
4. High Power Consumption in Power-down with External Clock
The power consumption in power down with an active external clock is about 10
times higher than when using internal RC or external oscillators.
Problem fix / Workaround
Stop the external clock when the device is in power down.
5. Asynchronous Oscillator does not stop in Power-down
The Asynchronous oscillator does not stop when entering power down mode. This
leads to higher power consumption than expected.
Problem fix / Workaround
Manually disable the asynchronous timer before entering power down.
21
ATmega48/88/168
2545DS–AVR–07/04
Errata ATmega88 The revision letter in this section refers to the revision of the ATmega88 device.
Rev. A •Writing to EEPROM does not work at low Operating Voltages
•Part may hang in reset
1. Writing to EEPROM does not work at low operating voltages
Writing to the EEPROM does not work at low voltages.
Problem Fix/Workaround
Do not write the EEPROM at voltages below 4.5 Volts.
This will be corrected in rev. B.
2. Part may hang in reset
Some parts may get stuck in a reset state when a reset signal is applied when the
internal reset state-machine is in a specific state. The internal reset state-machine is
in this state for approximately 10 ns immediately before the part wakes up after a
reset, and in a 10 ns window when altering the system clock prescaler. The problem
is most often seen during In-System Programming of the device. There are theoreti-
cal possibilities of this happening also in run-mode. The following three cases can
trigger the device to get stuck in a reset-state:
- Two succeeding resets are applied where the second reset occurs in the 10ns win-
dow before the device is out of the reset-state caused by the first reset.
- A reset is applied in a 10 ns window while the system clock prescaler value is
updated by software.
- Leaving SPI-programming mode generates an internal reset signal that can trigger
this case.
The two first cases can occur during normal operating mode, while the last case
occurs only during programming of the device.
Problem Fix/Workaround
The first case can be avoided during run-mode by ensuring that only one reset
source is active. If an external reset push button is used, the reset start-up time
should be selected such that the reset line is fully debounced during the start-up
time.
The second case can be avoided by not using the system clock prescaler.
The third case occurs during In-System programming only. It is most frequently
seen when using the internal RC at maximum frequency.
If the device gets stuck in the reset-state, turn power off, then on again to get the
device out of this state.
22 ATmega48/88/168
2545DS–AVR–07/04
Errata ATmega168 The revision letter in this section refers to the revision of the ATmega168 device.
Rev A •Wrong values read after Erase Only operation
•Part may hang in reset
1. Wrong values read after Erase Only operation
At supply voltages below 2.7 V, an EEPROM location that is erased by the Erase
Only operation may read as programmed (0x00).
Problem Fix/Workaround
If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write
operation with 0xFF as data in order to erase a location. In any case, the Write Only
operation can be used as intended. Thus no special considerations are needed as
long as the erased location is not read before it is programmed.
2. Part may hang in reset
Some parts may get stuck in a reset state when a reset signal is applied when the
internal reset state-machine is in a specific state. The internal reset state-machine is
in this state for approximately 10 ns immediately before the part wakes up after a
reset, and in a 10 ns window when altering the system clock prescaler. The problem
is most often seen during In-System Programming of the device. There are theoreti-
cal possibilities of this happening also in run-mode. The following three cases can
trigger the device to get stuck in a reset-state:
- Two succeeding resets are applied where the second reset occurs in the 10ns win-
dow before the device is out of the reset-state caused by the first reset.
- A reset is applied in a 10 ns window while the system clock prescaler value is
updated by software.
- Leaving SPI-programming mode generates an internal reset signal that can trigger
this case.
The two first cases can occur during normal operating mode, while the last case
occurs only during programming of the device.
Problem Fix/Workaround
The first case can be avoided during run-mode by ensuring that only one reset
source is active. If an external reset push button is used, the reset start-up time
should be selected such that the reset line is fully debounced during the start-up
time.
The second case can be avoided by not using the system clock prescaler.
The third case occurs during In-System programming only. It is most frequently
seen when using the internal RC at maximum frequency.
If the device gets stuck in the reset-state, turn power off, then on again to get the
device out of this state.
23
ATmega48/88/168
2545DS–AVR–07/04
Datasheet Change
Log
Please note that the referring page numbers in this section are referred to this docu-
ment. The referring revision in this section are referring to the document revision.
Changes from Rev.
2545C-04/04 to Rev.
2545D-07/04
Changes from Rev.
2545B-01/04 to Rev.
2545C-04/04
Changes from Rev.
2545A-09/03 to Rev.
2545B-01/04
1. Updated instructions used with WDTCSR in relevant code examples.
2. Updated Table 8 on page 28, Table 21 on page 43, Table 112 on page
269, Table 114 on page 269, and Table 131 on page 288.
3. Updated “System Clock Prescaler” on page 33.
4. Moved “Timer/Counter2 Interrupt Mask Register – TIMSK2” and
“Timer/Counter2 Interrupt Flag Register – TIFR2” to
“8-bit Timer/Counter Register Description” on page 143.
5. Updated cross-reference in “Electrical Interconnection” on page 199.
6. Updated equation in “Bit Rate Generator Unit” on page 204.
7. Added “Page Size” on page 274.
8. Updated “Serial Programming Algorithm” on page 287.
9. Updated “Ordering Information” for “ATmega168” on page 16
10. Updated “Errata ATmega88” on page 21 and “Errata ATmega168” on
page 22.
1. Speed Grades changed:
- 12MHz to 10MHz
- 24MHz to 20MHz
2. Updated “Maximum Speed vs. VCC” on page 293.
3. Updated “Ordering Information” on page 14.
4. Updated “Errata ATmega88” on page 21.
1. Added PDIP to “I/O and Packages”, updated “Speed Grade” and Power
Consumption Estimates in “Features” on page 1.
2. Updated “Stack Pointer” on page 11 with RAMEND as recommended
Stack Pointer value.
3. Added section “Power Reduction Register” on page 37 and a note
regarding the use of the PRR bits to 2-wire, Timer/Counters, USART,
Analog Comparator and ADC sections.
4. Updated “Watchdog Timer” on page 46.
5. Updated Figure 55 on page 125 and Table 56 on page 126.
6. Extra Compare Match Interrupt OCF2B added to features in section “8-
bit Timer/Counter2 with PWM and Asynchronous Operation” on page
132
7. Updated Table 19 on page 37, Table 102 on page 245, Table 118 to Table
121 on page 272 to 273 and Table 98 on page 236. Added note 2 to Table
115 on page 270. Fixed typo in Table 42 on page 81.
8. Updated whole “ATmega48/88/168 Typical Characteristics – Preliminary
Data” on page 298.
9. Added item 2 to 5 in “Errata ATmega48” on page 20.
24 ATmega48/88/168
2545DS–AVR–07/04
10. Renamed the following bits:
- SPMEN to SELFPRGEN
- PSR2 to PSRASY
- PSR10 to PSRSYNC
- Watchdog Reset to Watchdog System Reset
11. Updated C code examples containing old IAR syntax.
12. Updated BLBSET description in “Store Program Memory Control and
Status Register – SPMCSR” on page 260.
Printed on recycled paper.
Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard
warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any
errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and
does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are
granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel’s products are not authorized for use
as critical components in life support devices or systems.
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