Datasheet
Table Of Contents
- Features
- 1. Pin Configurations
- 2. Overview
- 3. Resources
- 4. Data Retention
- 5. About Code Examples
- 6. Capacitive touch sensing
- 7. AVR CPU Core
- 8. AVR Memories
- 9. System Clock and Clock Options
- 10. Power Management and Sleep Modes
- 11. System Control and Reset
- 12. Interrupts
- 13. External Interrupts
- 13.1 Pin Change Interrupt Timing
- 13.2 Register Description
- 13.2.1 EICRA – External Interrupt Control Register A
- 13.2.2 EIMSK – External Interrupt Mask Register
- 13.2.3 EIFR – External Interrupt Flag Registe
- 13.2.4 PCMSK3 – Pin Change Mask Register 3(1)
- 13.2.5 PCMSK2 – Pin Change Mask Register 2(1)
- 13.2.6 PCMSK1 – Pin Change Mask Register 1
- 13.2.7 PCMSK0 – Pin Change Mask Register 0
- 14. I/O-Ports
- 14.1 Overview
- 14.2 Ports as General Digital I/O
- 14.3 Alternate Port Functions
- 14.4 Register Description
- 14.4.1 MCUCR – MCU Control Register
- 14.4.2 PORTA – Port A Data Register
- 14.4.3 DDRA – Port A Data Direction Register
- 14.4.4 PINA – Port A Input Pins Address
- 14.4.5 PORTB – Port B Data Register
- 14.4.6 DDRB – Port B Data Direction Register
- 14.4.7 PINB – Port B Input Pins Address
- 14.4.8 PORTC – Port C Data Register
- 14.4.9 DDRC – Port C Data Direction Register
- 14.4.10 PINC – Port C Input Pins Address
- 14.4.11 PORTD – Port D Data Register
- 14.4.12 DDRD – Port D Data Direction Register
- 14.4.13 PIND – Port D Input Pins Address
- 14.4.14 PORTE – Port E Data Register
- 14.4.15 DDRE – Port E Data Direction Register
- 14.4.16 PINE – Port E Input Pins Address
- 14.4.17 PORTF – Port F Data Register
- 14.4.18 DDRF – Port F Data Direction Register
- 14.4.19 PINF – Port F Input Pins Address
- 14.4.20 PORTG – Port G Data Register
- 14.4.21 DDRG – Port G Data Direction Register
- 14.4.22 PING – Port G Input Pins Address
- 14.4.23 PORTH – Port H Data Register(1)
- 14.4.24 DDRH – Port H Data Direction Register(1)
- 14.4.25 PINH – Port H Input Pins Address(1)
- 14.4.26 PORTJ – Port J Data Register(1)
- 14.4.27 DDRJ – Port J Data Direction Register(1)
- 14.4.28 PINJ – Port J Input Pins Address(1)
- 15. 8-bit Timer/Counter0 with PWM
- 16. Timer/Counter0 and Timer/Counter1 Prescalers
- 17. 16-bit Timer/Counter1
- 17.1 Features
- 17.2 Overview
- 17.3 Accessing 16-bit Registers
- 17.4 Timer/Counter Clock Sources
- 17.5 Counter Unit
- 17.6 Input Capture Unit
- 17.7 Output Compare Units
- 17.8 Compare Match Output Unit
- 17.9 Modes of Operation
- 17.10 Timer/Counter Timing Diagrams
- 17.11 Register Description
- 17.11.1 TCCR1A – Timer/Counter1 Control Register A
- 17.11.2 TCCR1B – Timer/Counter1 Control Register B
- 17.11.3 TCCR1C – Timer/Counter1 Control Register C
- 17.11.4 TCNT1H and TCNT1L – Timer/Counter1
- 17.11.5 OCR1AH and OCR1AL – Output Compare Register 1 A
- 17.11.6 OCR1BH and OCR1BL – Output Compare Register 1 B
- 17.11.7 ICR1H and ICR1L – Input Capture Register 1
- 17.11.8 TIMSK1 – Timer/Counter1 Interrupt Mask Register
- 17.11.9 TIFR1 – Timer/Counter1 Interrupt Flag Register
- 18. 8-bit Timer/Counter2 with PWM and Asynchronous Operation
- 18.1 Features
- 18.2 Overview
- 18.3 Timer/Counter Clock Sources
- 18.4 Counter Unit
- 18.5 Output Compare Unit
- 18.6 Compare Match Output Unit
- 18.7 Modes of Operation
- 18.8 Timer/Counter Timing Diagrams
- 18.9 Asynchronous Operation of Timer/Counter2
- 18.10 Timer/Counter Prescaler
- 18.11 Register Description
- 18.11.1 TCCR2A – Timer/Counter Control Register A
- 18.11.2 TCNT2 – Timer/Counter Register
- 18.11.3 OCR2A – Output Compare Register A
- 18.11.4 ASSR – Asynchronous Status Register
- 18.11.5 TIMSK2 – Timer/Counter2 Interrupt Mask Register
- 18.11.6 TIFR2 – Timer/Counter2 Interrupt Flag Register
- 18.11.7 GTCCR – General Timer/Counter Control Register
- 19. SPI – Serial Peripheral Interface
- 20. USART0
- 20.1 Features
- 20.2 Overview
- 20.3 Clock Generation
- 20.4 Frame Formats
- 20.5 USART Initialization
- 20.6 Data Transmission – The USART Transmitter
- 20.7 Data Reception – The USART Receiver
- 20.8 Asynchronous Data Reception
- 20.9 Multi-processor Communication Mode
- 20.10 Examples of Baud Rate Setting
- 20.11 Register Description
- 21. USI – Universal Serial Interface
- 22. Analog Comparator
- 23. Analog to Digital Converter
- 24. JTAG Interface and On-chip Debug System
- 25. IEEE 1149.1 (JTAG) Boundary-scan
- 26. Boot Loader Support – Read-While-Write Self-Programming
- 26.1 Features
- 26.2 Overview
- 26.3 Application and Boot Loader Flash Sections
- 26.4 Read-While-Write and No Read-While-Write Flash Sections
- 26.5 Boot Loader Lock Bits
- 26.6 Entering the Boot Loader Program
- 26.7 Addressing the Flash During Self-Programming
- 26.8 Self-Programming the Flash
- 26.8.1 Performing Page Erase by SPM
- 26.8.2 Filling the Temporary Buffer (Page Loading)
- 26.8.3 Performing a Page Write
- 26.8.4 Using the SPM Interrupt
- 26.8.5 Consideration While Updating BLS
- 26.8.6 Prevent Reading the RWW Section During Self-Programming
- 26.8.7 Setting the Boot Loader Lock Bits by SPM
- 26.8.8 EEPROM Write Prevents Writing to SPMCSR
- 26.8.9 Reading the Fuse and Lock Bits from Software
- 26.8.10 Preventing Flash Corruption
- 26.8.11 Programming Time for Flash when Using SPM
- 26.8.12 Simple Assembly Code Example for a Boot Loader
- 26.8.13 Atmel ATmega325/3250/645/6450 Boot Loader Parameters
- 26.9 Register Description
- 27. Memory Programming
- 27.1 Program And Data Memory Lock Bits
- 27.2 Fuse Bits
- 27.3 Signature Bytes
- 27.4 Calibration Byte
- 27.5 Parallel Programming Parameters, Pin Mapping, and Commands
- 27.6 Parallel Programming
- 27.6.1 Enter Programming Mode
- 27.6.2 Considerations for Efficient Programming
- 27.6.3 Chip Erase
- 27.6.4 Programming the Flash
- 27.6.5 Programming the EEPROM
- 27.6.6 Reading the Flash
- 27.6.7 Reading the EEPROM
- 27.6.8 Programming the Fuse Low Bits
- 27.6.9 Programming the Fuse High Bits
- 27.6.10 Programming the Extended Fuse Bits
- 27.6.11 Programming the Lock Bits
- 27.6.12 Reading the Fuse and Lock Bits
- 27.6.13 Reading the Signature Bytes
- 27.6.14 Reading the Calibration Byte
- 27.6.15 Parallel Programming Characteristics
- 27.7 Serial Downloading
- 27.8 Programming via the JTAG Interface
- 27.8.1 Programming Specific JTAG Instructions
- 27.8.2 AVR_RESET (0xC)
- 27.8.3 PROG_ENABLE (0x4)
- 27.8.4 PROG_COMMANDS (0x5)
- 27.8.5 PROG_PAGELOAD (0x6)
- 27.8.6 PROG_PAGEREAD (0x7)
- 27.8.7 Data Registers
- 27.8.8 Reset Register
- 27.8.9 Programming Enable Register
- 27.8.10 Programming Command Register
- 27.8.11 Flash Data Byte Register
- 27.8.12 Programming Algorithm
- 27.8.13 Entering Programming Mode
- 27.8.14 Leaving Programming Mode
- 27.8.15 Performing Chip Erase
- 27.8.16 Programming the Flash
- 27.8.17 Reading the Flash
- 27.8.18 Programming the EEPROM
- 27.8.19 Reading the EEPROM
- 27.8.20 Programming the Fuses
- 27.8.21 Programming the Lock Bits
- 27.8.22 Reading the Fuses and Lock Bits
- 27.8.23 Reading the Signature Bytes
- 27.8.24 Reading the Calibration Byte
- 28. Electrical Characteristics
- 29. Typical Characteristics
- 29.1 Active Supply Current
- 29.2 Idle Supply Current
- 29.3 Supply Current of I/O modules
- 29.4 Power-down Supply Current
- 29.5 Power-save Supply Current
- 29.6 Standby Supply Current
- 29.7 Pin Pull-up
- 29.8 Pin Driver Strength
- 29.9 Pin Thresholds and hysteresis
- 29.10 BOD Thresholds and Analog Comparator Offset
- 29.11 Internal Oscillator Speed
- 29.12 Current Consumption of Peripheral Units
- 29.13 Current Consumption in Reset and Reset Pulsewidth
- 30. Register Summary
- 31. Instruction Set Summary
- 32. Ordering Information
- 33. Packaging Information
- 34. Errata
- 35. Datasheet Revision History
- 35.1 Rev. 2570N – 05/11
- 35.2 Rev. 2570M – 04/11
- 35.3 Rev. 2570L – 08/07
- 35.4 Rev. 2570K – 04/07
- 35.5 Rev. 2570J – 11/06
- 35.6 Rev. 2570I – 07/06
- 35.7 Rev. 2570H – 06/06
- 35.8 Rev. 2570G – 04/06
- 35.9 Rev. 2570F – 03/06
- 35.10 Rev. 2570E – 03/06
- 35.11 Rev. 2570D – 05/05
- 35.12 Rev. 2570C – 11/04
- 35.13 Rev. 2570B – 09/04
- 35.14 Rev. 2570A – 09/04
- Table of Contents
111
2570N–AVR–05/11
ATmega325/3250/645/6450
cleared by software (writing a logical one to the I/O bit location). For measuring frequency only,
the clearing of the ICF1 Flag is not required (if an interrupt handler is used).
17.7 Output Compare Units
The 16-bit comparator continuously compares TCNT1 with the Output Compare Register
(OCR1x). If TCNT equals OCR1x the comparator signals a match. A match will set the Output
Compare Flag (OCF1x) at the next timer clock cycle. If enabled (OCIE1x = 1), the Output Com-
pare Flag generates an Output Compare interrupt. The OCF1x Flag is automatically cleared
when the interrupt is executed. Alternatively the OCF1x Flag can be cleared by software by writ-
ing a logical one to its I/O bit location. The Waveform Generator uses the match signal to
generate an output according to operating mode set by the Waveform Generation mode
(WGM13:0) bits and Compare Output mode (COM1x1:0) bits. The TOP and BOTTOM signals
are used by the Waveform Generator for handling the special cases of the extreme values in
some modes of operation (See “Modes of Operation” on page 114.)
A special feature of Output Compare unit A allows it to define the Timer/Counter TOP value (i.e.,
counter resolution). In addition to the counter resolution, the TOP value defines the period time
for waveforms generated by the Waveform Generator.
Figure 17-4 shows a block diagram of the Output Compare unit. The small “n” in the register and
bit names indicates the device number (n = 1
for Timer/Counter 1), and the “x” indicates Output
Compare unit (A/B). The elements of the block diagram that are not directly a part of the Output
Compare unit are gray shaded.
Figure 17-4. Output Compare Unit, Block Diagram
The OCR1x Register is double buffered when using any of the twelve Pulse Width Modulation
(PWM) modes. For the Normal and Clear Timer on Compare (CTC) modes of operation, the
double buffering is disabled. The double buffering synchronizes the update of the OCR1x Com-
pare Register to either TOP or BOTTOM of the counting sequence. The synchronization
OCFnx (Int.Req.)
=
(16-bit Comparator )
OCRnx Buffer (16-bit Register)
OCRnxH Buf. (8-bit)
OCnx
TEMP (8-bit)
DATA BUS
(8-bit)
OCRnxL Buf. (8-bit)
TCNTn (16-bit Counter)
TCNTnH (8-bit) TCNTnL (8-bit)
COMnx1:0WGMn3:0
OCRnx (16-bit Register)
OCRnxH (8-bit) OCRnxL (8-bit)
Waveform Generator
TOP
BOTTOM