Datasheet
Table Of Contents
- Introduction
- Features
- Table of Contents
- 1. Description
- 2. Configuration Summary
- 3. Ordering Information
- 4. Block Diagram
- 5. Pin Configurations
- 6. Resources
- 7. Data Retention
- 8. About Code Examples
- 9. Capacitive Touch Sensing
- 10. AVR CPU Core
- 11. AVR Memories
- 12. System Clock and Clock Options
- 13. Power Management and Sleep Modes
- 14. System Control and Reset
- 15. Interrupts
- 16. External Interrupts
- 17. I/O Ports
- 17.1. Overview
- 17.2. Ports as General Digital I/O
- 17.3. Alternate Port Functions
- 17.4. Register Description
- 17.4.1. SFIOR – Special Function IO Register
- 17.4.2. PORTA – Port A Data Register
- 17.4.3. DDRA – Port A Data Direction Register
- 17.4.4. PINA – Port A Input Pins Address
- 17.4.5. PORTB – The Port B Data Register
- 17.4.6. DDRB – The Port B Data Direction Register
- 17.4.7. PINB – The Port B Input Pins Address
- 17.4.8. PORTC – The Port C Data Register
- 17.4.9. DDRC – The Port C Data Direction Register
- 17.4.10. PINC – The Port C Input Pins Address
- 17.4.11. PORTD – The Port D Data Register
- 17.4.12. DDRD – The Port D Data Direction Register
- 17.4.13. PIND – The Port D Input Pins Address
- 18. Timer/Counter0 and Timer/Counter1 Prescalers
- 19. 16-bit Timer/Counter1
- 19.1. Features
- 19.2. Overview
- 19.3. Accessing 16-bit Registers
- 19.4. Timer/Counter Clock Sources
- 19.5. Counter Unit
- 19.6. Input Capture Unit
- 19.7. Output Compare Units
- 19.8. Compare Match Output Unit
- 19.9. Modes of Operation
- 19.10. Timer/Counter Timing Diagrams
- 19.11. Register Description
- 19.11.1. TCCR1A – Timer/Counter1 Control Register A
- 19.11.2. TCCR1B – Timer/Counter1 Control Register B
- 19.11.3. TCNT1L – Timer/Counter1 Low byte
- 19.11.4. TCNT1H – Timer/Counter1 High byte
- 19.11.5. OCR1AL – Output Compare Register 1 A Low byte
- 19.11.6. OCR1AH – Output Compare Register 1 A High byte
- 19.11.7. OCR1BL – Output Compare Register 1 B Low byte
- 19.11.8. OCR1BH – Output Compare Register 1 B High byte
- 19.11.9. ICR1L – Input Capture Register 1 Low byte
- 19.11.10. ICR1H – Input Capture Register 1 High byte
- 19.11.11. TIMSK – Timer/Counter Interrupt Mask Register
- 19.11.12. TIFR – Timer/Counter Interrupt Flag Register
- 20. 8-bit Timer/Counter2 with PWM and Asynchronous Operation
- 20.1. Features
- 20.2. Overview
- 20.3. Timer/Counter Clock Sources
- 20.4. Counter Unit
- 20.5. Output Compare Unit
- 20.6. Compare Match Output Unit
- 20.7. Modes of Operation
- 20.8. Timer/Counter Timing Diagrams
- 20.9. Asynchronous Operation of the Timer/Counter
- 20.10. Timer/Counter Prescaler
- 20.11. Register Description
- 20.11.1. TCCR2 – Timer/Counter Control Register
- 20.11.2. TCNT0 – Timer/Counter Register
- 20.11.3. OCR0 – Output Compare Register
- 20.11.4. ASSR – Asynchronous Status Register
- 20.11.5. TIMSK – Timer/Counter Interrupt Mask Register
- 20.11.6. TIFR – Timer/Counter Interrupt Flag Register
- 20.11.7. SFIOR – Special Function IO Register
- 21. 8-bit Timer/Counter0 with PWM
- 22. SPI – Serial Peripheral Interface
- 23. USART - Universal Synchronous and Asynchronous serial Receiver and Transmitter
- 23.1. Features
- 23.2. Overview
- 23.3. Clock Generation
- 23.4. Frame Formats
- 23.5. USART Initialization
- 23.6. Data Transmission – The USART Transmitter
- 23.7. Data Reception – The USART Receiver
- 23.8. Asynchronous Data Reception
- 23.9. Multi-Processor Communication Mode
- 23.10. Accessing UBRRH/UCSRC Registers
- 23.11. Register Description
- 23.12. Examples of Baud Rate Setting
- 24. TWI - Two-wire Serial Interface
- 25. AC - Analog Comparator
- 26. ADC - Analog to Digital Converter
- 26.1. Features
- 26.2. Overview
- 26.3. Starting a Conversion
- 26.4. Prescaling and Conversion Timing
- 26.5. Changing Channel or Reference Selection
- 26.6. ADC Noise Canceler
- 26.7. ADC Conversion Result
- 26.8. Register Description
- 26.8.1. ADMUX – ADC Multiplexer Selection Register
- 26.8.2. ADCSRA – ADC Control and Status Register A
- 26.8.3. ADCL – ADC Data Register Low (ADLAR=0)
- 26.8.4. ADCH – ADC Data Register High (ADLAR=0)
- 26.8.5. ADCL – ADC Data Register Low (ADLAR=1)
- 26.8.6. ADCH – ADC Data Register High (ADLAR=1)
- 26.8.7. SFIOR – Special Function IO Register
- 27. JTAG Interface and On-chip Debug System
- 27.1. Features
- 27.2. Overview
- 27.3. TAP – Test Access Port
- 27.4. TAP Controller
- 27.5. Using the Boundary-scan Chain
- 27.6. Using the On-chip Debug System
- 27.7. On-chip Debug Specific JTAG Instructions
- 27.8. Using the JTAG Programming Capabilities
- 27.9. Bibliography
- 27.10. IEEE 1149.1 (JTAG) Boundary-scan
- 27.11. Data Registers
- 27.12. Boundry-scan Specific JTAG Instructions
- 27.13. Boundary-scan Chain
- 27.14. ATmega32A Boundary-scan Order
- 27.15. Boundary-scan Description Language Files
- 27.16. Register Description
- 28. BTLDR - Boot Loader Support – Read-While-Write Self-Programming
- 28.1. Features
- 28.2. Overview
- 28.3. Application and Boot Loader Flash Sections
- 28.4. Read-While-Write and No Read-While-Write Flash Sections
- 28.5. Boot Loader Lock Bits
- 28.6. Entering the Boot Loader Program
- 28.7. Addressing the Flash During Self-Programming
- 28.8. Self-Programming the Flash
- 28.8.1. Performing Page Erase by SPM
- 28.8.2. Filling the Temporary Buffer (Page Loading)
- 28.8.3. Performing a Page Write
- 28.8.4. Using the SPM Interrupt
- 28.8.5. Consideration While Updating Boot Loader Section (BLS)
- 28.8.6. Prevent Reading the RWW Section During Self-Programming
- 28.8.7. Setting the Boot Loader Lock Bits by SPM
- 28.8.8. EEPROM Write Prevents Writing to SPMCR
- 28.8.9. Reading the Fuse and Lock Bits from Software
- 28.8.10. Preventing Flash Corruption
- 28.8.11. Programming Time for Flash when Using SPM
- 28.8.12. Simple Assembly Code Example for a Boot Loader
- 28.8.13. ATmega32A Boot Loader Parameters
- 28.9. Register Description
- 29. Memory Programming
- 29.1. Program and Data Memory Lock Bits
- 29.2. Fuse Bits
- 29.3. Signature Bytes
- 29.4. Signature Bytes
- 29.5. Calibration Byte
- 29.6. Parallel Programming Parameters, Pin Mapping, and Commands
- 29.7. Parallel Programming
- 29.7.1. Enter Programming Mode
- 29.7.2. Considerations for Efficient Programming
- 29.7.3. Chip Erase
- 29.7.4. Programming the Flash
- 29.7.5. Programming the EEPROM
- 29.7.6. Reading the Flash
- 29.7.7. Reading the EEPROM
- 29.7.8. Programming the Fuse Low Bits
- 29.7.9. Programming the Fuse High Bits
- 29.7.10. Programming the Lock Bits
- 29.7.11. Reading the Fuse and Lock Bits
- 29.7.12. Reading the Signature Bytes
- 29.7.13. Reading the Calibration Byte
- 29.7.14. Parallel Programming Characteristics
- 29.8. Serial Downloading
- 29.9. Serial Programming Pin Mapping
- 29.10. Programming Via the JTAG Interface
- 29.10.1. Programming Specific JTAG Instructions
- 29.10.2. AVR_RESET (0xC)
- 29.10.3. PROG_ENABLE (0x4)
- 29.10.4. PROG_COMMANDS (0x5)
- 29.10.5. PROG_PAGELOAD (0x6)
- 29.10.6. PROG_PAGEREAD (0x7)
- 29.10.7. Data Registers
- 29.10.8. Reset Register
- 29.10.9. Programming Enable Register
- 29.10.10. Programming Command Register
- 29.10.11. Virtual Flash Page Load Register
- 29.10.12. Virtual Flash Page Read Register
- 29.10.13. Programming Algorithm
- 29.10.14. Entering Programming Mode
- 29.10.15. Leaving Programming Mode
- 29.10.16. Performing Chip Erase
- 29.10.17. Programming the Flash
- 29.10.18. Reading the Flash
- 29.10.19. Programming the EEPROM
- 29.10.20. Reading the EEPROM
- 29.10.21. Programming the Fuses
- 29.10.22. Programming the Lock Bits
- 29.10.23. Reading the Fuses and Lock Bits
- 29.10.24. Reading the Signature Bytes
- 29.10.25. Reading the Calibration Byte
- 30. Electrical Characteristics
- 31. Typical Characteristics
- 31.1. Active Supply Current
- 31.2. Idle Supply Current
- 31.3. Power-down Supply Current
- 31.4. Power-save Supply current
- 31.5. Standby Supply Current
- 31.6. Pin Pull-up
- 31.7. Pin Driver Strength
- 31.8. Pin Thresholds and Hysteresis
- 31.9. BOD Thresholds and Analog Comparator Offset
- 31.10. Internal Oscillator Speed
- 31.11. Current Consumption of Peripheral Units
- 31.12. Current Consumption in Reset and Reset Pulsewidth
- 32. Register Summary
- 33. Instruction Set Summary
- 34. Packaging Information
- 35. Errata
- 36. Datasheet Revision History
24.4.4. Data Packet Format
All data packets transmitted on the TWI bus are nine bits long, consisting of one data byte and an
acknowledge bit. During a data transfer, the Master generates the clock and the START and STOP
conditions, while the Receiver is responsible for acknowledging the reception. An Acknowledge (ACK) is
signalled by the Receiver pulling the SDA line low during the ninth SCL cycle. If the Receiver leaves the
SDA line high, a NACK is signalled. When the Receiver has received the last byte, or for some reason
cannot receive any more bytes, it should inform the Transmitter by sending a NACK after the final byte.
The MSB of the data byte is transmitted first.
Figure 24-6. Data Packet Format
1 2 7 8 9
Data MSB Data LSB ACK
Aggregate
SD A
SDA from
Transmitter
SDA from
Receiv er
SCL from
Master
SLA+R/W Data Byte
ST OP, REPEA TED
ST AR T or Ne xt
Data Byte
24.4.5. Combining Address and Data Packets Into a Transmission
A transmission basically consists of a START condition, a SLA+R/W, one or more data packets and a
STOP condition. An empty message, consisting of a START followed by a STOP condition, is illegal. Note
that the Wired-ANDing of the SCL line can be used to implement handshaking between the Master and
the Slave. The Slave can extend the SCL low period by pulling the SCL line low. This is useful if the clock
speed set up by the Master is too fast for the Slave, or the Slave needs extra time for processing between
the data transmissions. The Slave extending the SCL low period will not affect the SCL high period, which
is determined by the Master. As a consequence, the Slave can reduce the TWI data transfer speed by
prolonging the SCL duty cycle.
The following figure depicts a typical data transmission. Note that several data bytes can be transmitted
between the SLA+R/W and the STOP condition, depending on the software protocol implemented by the
application software.
Figure 24-7. Typical Data Transmission
1 2 7 8 9
Data Byte
Data MSB Data LSB ACK
SD A
SCL
ST AR T
1 2 7 8 9
Addr MSB Addr LSB R/W ACK
SLA+R/W ST OP
Atmel ATmega32A [DATASHEET]
Atmel-8155I-ATmega32A_Datasheet_Complete-08/2016
226