Data Sheet
Table Of Contents
- Features
- 1. Pin Configurations
- 2. Overview
- 3. Resources
- 4. About Code Examples
- 5. AVR CPU Core
- 6. AVR Memories
- 7. System Clock and Clock Options
- 7.1 Clock Systems and their Distribution
- 7.2 Clock Sources
- 7.3 Low Power Crystal Oscillator
- 7.4 Full Swing Crystal Oscillator
- 7.5 Low Frequency Crystal Oscillator
- 7.6 Calibrated Internal RC Oscillator
- 7.7 128 kHz Internal Oscillator
- 7.8 External Clock
- 7.9 Clock Output Buffer
- 7.10 Timer/Counter Oscillator
- 7.11 System Clock Prescaler
- 7.12 Register Description
- 8. Power Management and Sleep Modes
- 9. System Control and Reset
- 10. Interrupts
- 11. External Interrupts
- 11.1 Pin Change Interrupt Timing
- 11.2 Register Description
- 11.2.1 EICRA - External Interrupt Control Register A
- 11.2.2 EIMSK - External Interrupt Mask Register
- 11.2.3 EIFR - External Interrupt Flag Register
- 11.2.4 PCICR - Pin Change Interrupt Control Register
- 11.2.5 PCIFR - Pin Change Interrupt Flag Register
- 11.2.6 PCMSK2 - Pin Change Mask Register 2
- 11.2.7 PCMSK1 - Pin Change Mask Register 1
- 11.2.8 PCMSK0 - Pin Change Mask Register 0
- 12. I/O-Ports
- 12.1 Overview
- 12.2 Ports as General Digital I/O
- 12.3 Alternate Port Functions
- 12.4 Register Description
- 12.4.1 MCUCR - MCU Control Register
- 12.4.2 PORTB - The Port B Data Register
- 12.4.3 DDRB - The Port B Data Direction Register
- 12.4.4 PINB - The Port B Input Pins Address
- 12.4.5 PORTC - The Port C Data Register
- 12.4.6 DDRC - The Port C Data Direction Register
- 12.4.7 PINC - The Port C Input Pins Address
- 12.4.8 PORTD - The Port D Data Register
- 12.4.9 DDRD - The Port D Data Direction Register
- 12.4.10 PIND - The Port D Input Pins Address
- 13. 8-bit Timer/Counter0 with PWM
- 13.1 Features
- 13.2 Overview
- 13.3 Timer/Counter Clock Sources
- 13.4 Counter Unit
- 13.5 Output Compare Unit
- 13.6 Compare Match Output Unit
- 13.7 Modes of Operation
- 13.8 Timer/Counter Timing Diagrams
- 13.9 Register Description
- 13.9.1 TCCR0A - Timer/Counter Control Register A
- 13.9.2 TCCR0B - Timer/Counter Control Register B
- 13.9.3 TCNT0 - Timer/Counter Register
- 13.9.4 OCR0A - Output Compare Register A
- 13.9.5 OCR0B - Output Compare Register B
- 13.9.6 TIMSK0 - Timer/Counter Interrupt Mask Register
- 13.9.7 TIFR0 - Timer/Counter 0 Interrupt Flag Register
- 14. 16-bit Timer/Counter1 with PWM
- 14.1 Features
- 14.2 Overview
- 14.3 Accessing 16-bit Registers
- 14.4 Timer/Counter Clock Sources
- 14.5 Counter Unit
- 14.6 Input Capture Unit
- 14.7 Output Compare Units
- 14.8 Compare Match Output Unit
- 14.9 Modes of Operation
- 14.10 Timer/Counter Timing Diagrams
- 14.11 Register Description
- 14.11.1 TCCR1A - Timer/Counter1 Control Register A
- 14.11.2 TCCR1B - Timer/Counter1 Control Register B
- 14.11.3 TCCR1C - Timer/Counter1 Control Register C
- 14.11.4 TCNT1H and TCNT1L - Timer/Counter1
- 14.11.5 OCR1AH and OCR1AL - Output Compare Register 1 A
- 14.11.6 OCR1BH and OCR1BL - Output Compare Register 1 B
- 14.11.7 ICR1H and ICR1L - Input Capture Register 1
- 14.11.8 TIMSK1 - Timer/Counter1 Interrupt Mask Register
- 14.11.9 TIFR1 - Timer/Counter1 Interrupt Flag Register
- 15. Timer/Counter0 and Timer/Counter1 Prescalers
- 16. 8-bit Timer/Counter2 with PWM and Asynchronous Operation
- 16.1 Features
- 16.2 Overview
- 16.3 Timer/Counter Clock Sources
- 16.4 Counter Unit
- 16.5 Output Compare Unit
- 16.6 Compare Match Output Unit
- 16.7 Modes of Operation
- 16.8 Timer/Counter Timing Diagrams
- 16.9 Asynchronous Operation of Timer/Counter2
- 16.10 Timer/Counter Prescaler
- 16.11 Register Description
- 16.11.1 TCCR2A - Timer/Counter Control Register A
- 16.11.2 TCCR2B - Timer/Counter Control Register B
- 16.11.3 TCNT2 - Timer/Counter Register
- 16.11.4 OCR2A - Output Compare Register A
- 16.11.5 OCR2B - Output Compare Register B
- 16.11.6 TIMSK2 - Timer/Counter2 Interrupt Mask Register
- 16.11.7 TIFR2 - Timer/Counter2 Interrupt Flag Register
- 16.11.8 ASSR - Asynchronous Status Register
- 16.11.9 GTCCR - General Timer/Counter Control Register
- 17. SPI - Serial Peripheral Interface
- 18. USART0
- 18.1 Features
- 18.2 Overview
- 18.3 Clock Generation
- 18.4 Frame Formats
- 18.5 USART Initialization
- 18.6 Data Transmission - The USART Transmitter
- 18.7 Data Reception - The USART Receiver
- 18.8 Asynchronous Data Reception
- 18.9 Multi-processor Communication Mode
- 18.10 Register Description
- 18.11 Examples of Baud Rate Setting
- 19. USART in SPI Mode
- 20. 2-wire Serial Interface
- 21. Analog Comparator
- 22. Analog-to-Digital Converter
- 23. debugWIRE On-chip Debug System
- 24. Self-Programming the Flash, ATmega48
- 25. Boot Loader Support - Read-While-Write Self-Programming, ATmega88 and ATmega168
- 25.1 Features
- 25.2 Overview
- 25.3 Application and Boot Loader Flash Sections
- 25.4 Read-While-Write and No Read-While-Write Flash Sections
- 25.5 Boot Loader Lock Bits
- 25.6 Entering the Boot Loader Program
- 25.7 Addressing the Flash During Self-Programming
- 25.8 Self-Programming the Flash
- 25.8.1 Performing Page Erase by SPM
- 25.8.2 Filling the Temporary Buffer (Page Loading)
- 25.8.3 Performing a Page Write
- 25.8.4 Using the SPM Interrupt
- 25.8.5 Consideration While Updating BLS
- 25.8.6 Prevent Reading the RWW Section During Self-Programming
- 25.8.7 Setting the Boot Loader Lock Bits by SPM
- 25.8.8 EEPROM Write Prevents Writing to SPMCSR
- 25.8.9 Reading the Fuse and Lock Bits from Software
- 25.8.10 Preventing Flash Corruption
- 25.8.11 Programming Time for Flash when Using SPM
- 25.8.12 Simple Assembly Code Example for a Boot Loader
- 25.8.13 ATmega88 Boot Loader Parameters
- 25.8.14 ATmega168 Boot Loader Parameters
- 25.9 Register Description
- 26. Memory Programming
- 26.1 Program And Data Memory Lock Bits
- 26.2 Fuse Bits
- 26.3 Signature Bytes
- 26.4 Calibration Byte
- 26.5 Page Size
- 26.6 Parallel Programming Parameters, Pin Mapping, and Commands
- 26.7 Parallel Programming
- 26.7.1 Enter Programming Mode
- 26.7.2 Considerations for Efficient Programming
- 26.7.3 Chip Erase
- 26.7.4 Programming the Flash
- 26.7.5 Programming the EEPROM
- 26.7.6 Reading the Flash
- 26.7.7 Reading the EEPROM
- 26.7.8 Programming the Fuse Low Bits
- 26.7.9 Programming the Fuse High Bits
- 26.7.10 Programming the Extended Fuse Bits
- 26.7.11 Programming the Lock Bits
- 26.7.12 Reading the Fuse and Lock Bits
- 26.7.13 Reading the Signature Bytes
- 26.7.14 Reading the Calibration Byte
- 26.7.15 Parallel Programming Characteristics
- 26.8 Serial Downloading
- 27. Electrical Characteristics
- 27.1 Absolute Maximum Ratings*
- 27.2 DC Characteristics ATmega48/88/168*
- 27.3 Speed Grades
- 27.4 Clock Characteristics
- 27.5 System and Reset Characteristics
- 27.6 2-wire Serial Interface Characteristics
- 27.7 SPI Timing Characteristics
- 27.8 ADC Characteristics - Preliminary Data
- 27.9 Parallel Programming Characteristics
- 28. Typical Characteristics - Preliminary Data
- 28.1 Active Supply Current
- 28.2 Idle Supply Current
- 28.3 Supply Current of I/O modules
- 28.4 Power-Down Supply Current
- 28.5 Power-Save Supply Current
- 28.6 Standby Supply Current
- 28.7 Pin Pull-up
- 28.8 Pin Driver Strength
- 28.9 Pin Thresholds and Hysteresis
- 28.10 BOD Thresholds and Analog Comparator Offset
- 28.11 Internal Oscillator Speed
- 28.12 Current Consumption of Peripheral Units
- 28.13 Current Consumption in Reset and Reset Pulse width
- 29. Register Summary
- 30. Instruction Set Summary
- 31. Ordering Information
- 32. Packaging Information
- 33. Errata
- 34. Datasheet Revision History
- Table of Contents
344
2545K–AVR–04/07
ATmega48/88/168
(0x7D) Reserved – – – – – – – –
(0x7C) ADMUX REFS1 REFS0 ADLAR – MUX3 MUX2 MUX1 MUX0 255
(0x7B) ADCSRB –ACME – – – ADTS2 ADTS1 ADTS0 258
(0x7A) ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 256
(0x79) ADCH ADC Data Register High byte 258
(0x78) ADCL ADC Data Register Low byte 258
(0x77) Reserved – – – – – – – –
(0x76) Reserved – – – – – – – –
(0x75) Reserved – – – – – – – –
(0x74) Reserved – – – – – – – –
(0x73) Reserved – – – – – – – –
(0x72) Reserved – – – – – – – –
(0x71) Reserved – – – – – – – –
(0x70) TIMSK2 – – – – – OCIE2B OCIE2A TOIE2 158
(0x6F) TIMSK1 – –ICIE1 – – OCIE1B OCIE1A TOIE1 135
(0x6E) TIMSK0 – – – – – OCIE0B OCIE0A TOIE0 106
(0x6D) PCMSK2 PCINT23 PCINT22 PCINT21 PCINT20 PCINT19 PCINT18 PCINT17 PCINT16 70
(0x6C) PCMSK1 – PCINT14 PCINT13 PCINT12 PCINT11 PCINT10 PCINT9 PCINT8 70
(0x6B) PCMSK0 PCINT7 PCINT6 PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 70
(0x6A) Reserved
– – – – – – – –
(0x69) EICRA
– – – –ISC11ISC10ISC01ISC00 67
(0x68) PCICR – – – – – PCIE2 PCIE1 PCIE0
(0x67) Reserved – – – – – – – –
(0x66) OSCCAL Oscillator Calibration Register 37
(0x65) Reserved – – – – – – – –
(0x64) PRR PRTWI PRTIM2 PRTIM0 – PRTIM1 PRSPI PRUSART0 PRADC 41
(0x63) Reserved – – – – – – – –
(0x62) Reserved – – – – – – – –
(0x61) CLKPR CLKPCE – – – CLKPS3 CLKPS2 CLKPS1 CLKPS0 37
(0x60) WDTCSR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0 53
0x3F (0x5F) SREG I T H S V N Z C 11
0x3E (0x5E) SPH – – – – – (SP10)
5.
SP9 SP8 13
0x3D (0x5D) SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 13
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 283
0x36 (0x56) Reserved – – – – – – – –
0x35 (0x55) MCUCR – – –PUD– – IVSEL IVCE
0x34 (0x54) MCUSR – – – – WDRF BORF EXTRF PORF
0x33 (0x53) SMCR – – – –SM2SM1SM0SE 39
0x32 (0x52) Reserved
– – – – – – – –
0x31 (0x51) Reserved
– – – – – – – –
0x30 (0x50) ACSR ACD ACBG ACO ACI ACIE ACIC ACIS1 ACIS0 242
0x2F (0x4F) Reserved
– – – – – – – –
0x2E (0x4E) SPDR SPI Data Register 170
0x2D (0x4D) SPSR SPIF WCOL – – – – – SPI2X 169
0x2C (0x4C) SPCR SPIE SPE DORD MSTR CPOL CPHA SPR1 SPR0 168
0x2B (0x4B) GPIOR2 General Purpose I/O Register 2 26
0x2A (0x4A) GPIOR1 General Purpose I/O Register 1 26
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 139/160
0x22 (0x42) EEARH (EEPROM Address Register High Byte)
5.
22
0x21 (0x41) EEARL EEPROM Address Register Low Byte 22
0x20 (0x40) EEDR EEPROM Data Register 22
0x1F (0x3F) EECR – – EEPM1 EEPM0 EERIE EEMPE EEPE EERE 22
0x1E (0x3E) GPIOR0 General Purpose I/O Register 0 26
0x1D (0x3D) EIMSK
– – – – – –INT1INT0 68
0x1C (0x3C) EIFR
– – – – – – INTF1 INTF0 68
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page