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. I/O Ports
- 13.1 Overview
- 13.2 Ports as General Digital I/O
- 13.3 Alternate Port Functions
- 13.4 Register Description
- 13.4.1 SFIOR – Special Function I/O Register
- 13.4.2 PORTA – Port A Data Register
- 13.4.3 DDRA – Port A Data Direction Register
- 13.4.4 PINA – Port A Input Pins Address
- 13.4.5 PORTB – Port B Data Register
- 13.4.6 DDRB – Port B Data Direction Register
- 13.4.7 PINB – Port B Input Pins Address
- 13.4.8 PORTC – Port C Data Register
- 13.4.9 DDRC – Port C Data Direction Register
- 13.4.10 PINC – Port C Input Pins Address
- 13.4.11 PORTD – Port D Data Register
- 13.4.12 DDRD – Port D Data Direction Register
- 13.4.13 PIND – Port D Input Pins Address
- 14. External Interrupts
- 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 Compare Match Output Unit
- 17.8 Modes of Operation
- 17.9 Timer/Counter Timing Diagrams
- 17.10 Register Description
- 17.10.1 TCCR1A – Timer/Counter1 Control Register A
- 17.10.2 TCCR1B – Timer/Counter1 Control Register B
- 17.10.3 TCNT1H and TCNT1L – Timer/Counter1
- 17.10.4 OCR1AH and OCR1AL – Output Compare Register 1 A
- 17.10.5 OCR1BH and OCR1BL – Output Compare Register 1 B
- 17.10.6 ICR1H and ICR1L – Input Capture Register 1
- 17.10.7 TIMSK – Timer/Counter Interrupt Mask Register(1)
- 17.10.8 TIFR – Timer/Counter 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 the Timer/Counter
- 18.10 Timer/Counter Prescaler
- 18.11 Register Description
- 18.11.1 TCCR2 – Timer/Counter Control Register
- 18.11.2 TCNT2 – Timer/Counter Register
- 18.11.3 OCR2 – Output Compare Register
- 18.11.4 ‘ASSR – Asynchronous Status Register
- 18.11.5 TIMSK – Timer/Counter Interrupt Mask Register
- 18.11.6 TIFR – Timer/Counter Interrupt Flag Register
- 18.11.7 SFIOR – Special Function IO Register
- 19. SPI – Serial Peripheral Interface
- 20. USART
- 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 Accessing UBRRH/ UCSRC Registers
- 20.11 Register Description
- 20.12 Examples of Baud Rate Setting
- 21. Two-wire 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 SPMCR
- 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 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 Page Size
- 27.6 Parallel Programming Parameters, Pin Mapping, and Commands
- 27.7 Parallel Programming
- 27.7.1 Enter Programming Mode
- 27.7.2 Considerations for Efficient Programming
- 27.7.3 Chip Erase
- 27.7.4 Programming the Flash
- 27.7.5 Programming the EEPROM
- 27.7.6 Reading the Flash
- 27.7.7 Reading the EEPROM
- 27.7.8 Programming the Fuse Low Bits
- 27.7.9 Programming the Fuse High Bits
- 27.7.10 Programming the Lock Bits
- 27.7.11 Reading the Fuse and Lock Bits
- 27.7.12 Reading the Signature Bytes
- 27.7.13 Reading the Calibration Byte
- 27.7.14 Parallel Programming Characteristics
- 27.8 SPI Serial Downloading
- 27.9 SPI Serial Programming Pin Mapping
- 27.10 Programming via the JTAG Interface
- 27.10.1 Programming Specific JTAG Instructions
- 27.10.2 AVR_RESET ($C)
- 27.10.3 PROG_ENABLE ($4)
- 27.10.4 PROG_COMMANDS ($5)
- 27.10.5 PROG_PAGELOAD ($6)
- 27.10.6 PROG_PAGEREAD ($7)
- 27.10.7 Data Registers
- 27.10.8 Reset Register
- 27.10.9 Programming Enable Register
- 27.10.10 Programming Command Register
- 27.10.11 Virtual Flash Page Load Register
- 27.10.12 Virtual Flash Page Read Register
- 27.10.13 Programming Algorithm
- 27.10.14 Entering Programming Mode
- 27.10.15 Leaving Programming Mode
- 27.10.16 Performing Chip Erase
- 27.10.17 Programming the Flash
- 27.10.18 Reading the Flash
- 27.10.19 Programming the EEPROM
- 27.10.20 Reading the EEPROM
- 27.10.21 Programming the Fuses
- 27.10.22 Programming the Lock Bits
- 27.10.23 Reading the Fuses and Lock Bits
- 27.10.24 Reading the Signature Bytes
- 27.10.25 Reading the Calibration Byte
- 28. Electrical Characteristics
- 29. Typical Characteristics
- 29.1 Active Supply Current
- 29.2 Idle Supply Current
- 29.3 Power-down Supply Current
- 29.4 Power-save Supply Current
- 29.5 Standby Supply Current
- 29.6 Pin Pull-up
- 29.7 Pin Driver Strength
- 29.8 Pin Thresholds and Hysteresis
- 29.9 BOD Thresholds and Analog Comparator Offset
- 29.10 Internal Oscillator Speed
- 29.11 Current Consumption of Peripheral Units
- 29.12 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
- Table of Contents
168
ATmega32A [DATASHEET]
Atmel-8155D-AVR-ATmega32A-Datasheet_02/2014
Note that all masters listen to the SCL line, effectively starting to count their SCL high and low time-out periods
when the combined SCL line goes high or low, respectively.
Figure 21-7. SCL Synchronization between Multiple Masters
Arbitration is carried out by all masters continuously monitoring the SDA line after outputting data. If the value read
from the SDA line does not match the value the master had output, it has lost the arbitration. Note that a master
can only lose arbitration when it outputs a high SDA value while another master outputs a low value. The losing
master should immediately go to slave mode, checking if it is being addressed by the winning master. The SDA
line should be left high, but losing masters are allowed to generate a clock signal until the end of the current data or
address packet. Arbitration will continue until only one master remains, and this may take many bits. If several
masters are trying to address the same slave, arbitration will continue into the data packet.
Figure 21-8. Arbitration between Two Masters
Note that arbitration is not allowed between:
• A REPEATED START condition and a data bit
• A STOP condition and a data bit
TA
low
TA
high
SCL from
Master A
SCL from
Master B
SCL bus
Line
TB
low
TB
high
Masters Start
Counting Low Period
Masters Start
Counting High Period
SDA from
Master A
SDA from
Master B
SDA Line
Synchronized
SCL Line
START
Master A Loses
Arbitration, SDA
A
SDA