Manual
Table Of Contents
- Features
- 1. Pin Configurations
- 2. Overview
- 3. Disclaimer
- 4. Resources
- 5. About Code Examples
- 6. Data Retention
- 7. AVR CPU Core
- 8. Memories
- 9. System Clock and their Distribution
- 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 Register
- 13.2.4 PCICR – Pin Change Interrupt Control Register
- 13.2.5 PCIFR – Pin Change Interrupt Flag Register
- 13.2.6 PCMSK3 – Pin Change Mask Register 3
- 13.2.7 PCMSK2 – Pin Change Mask Register 2
- 13.2.8 PCMSK1 – Pin Change Mask Register 1
- 13.2.9 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 PORTB – Port B Data Register
- 14.4.3 DDRB – Port B Data Direction Register
- 14.4.4 PINB – Port B Input Pins Address
- 14.4.5 PORTC – Port C Data Register
- 14.4.6 DDRC – Port C Data Direction Register
- 14.4.7 PINC – Port C Input Pins Address
- 14.4.8 PORTD – Port D Data Register
- 14.4.9 DDRD – Port D Data Direction Register
- 14.4.10 PIND – Port D Input Pins Address
- 14.4.11 PORTE – Port E Data Register
- 14.4.12 DDRE – Port E Data Direction Register
- 14.4.13 PINE – Port E Input Pins Address
- 15. 8-bit Timer/Counter0 with PWM
- 15.1 Features
- 15.2 Overview
- 15.3 Timer/Counter Clock Sources
- 15.4 Counter Unit
- 15.5 Output Compare Unit
- 15.6 Compare Match Output Unit
- 15.7 Modes of Operation
- 15.8 Timer/Counter Timing Diagrams
- 15.9 Register Description
- 15.9.1 TCCR0A – Timer/Counter Control Register A
- 15.9.2 TCCR0B – Timer/Counter Control Register B
- 15.9.3 TCNT0 – Timer/Counter Register
- 15.9.4 OCR0A – Output Compare Register A
- 15.9.5 OCR0B – Output Compare Register B
- 15.9.6 TIMSK0 – Timer/Counter Interrupt Mask Register
- 15.9.7 TIFR0 – Timer/Counter 0 Interrupt Flag Register
- 16. 16-bit Timer/Counter1 with PWM
- 16.1 Features
- 16.2 Overview
- 16.3 Accessing 16-bit Registers
- 16.4 Timer/Counter Clock Sources
- 16.5 Counter Unit
- 16.6 Input Capture Unit
- 16.7 Output Compare Units
- 16.8 Compare Match Output Unit
- 16.9 Modes of Operation
- 16.10 Timer/Counter Timing Diagrams
- 16.11 Register Description
- 16.11.1 TCCR1A – Timer/Counter1 Control Register A
- 16.11.2 TCCR1B – Timer/Counter1 Control Register B
- 16.11.3 TCCR1C – Timer/Counter1 Control Register C
- 16.11.4 TCNT1H and TCNT1L – Timer/Counter1
- 16.11.5 OCR1AH and OCR1AL – Output Compare Register 1 A
- 16.11.6 OCR1BH and OCR1BL – Output Compare Register 1 B
- 16.11.7 ICR1H and ICR1L – Input Capture Register 1
- 16.11.8 TIMSK1 – Timer/Counter1 Interrupt Mask Register
- 16.11.9 TIFR1 – Timer/Counter1 Interrupt Flag Register
- 17. Timer/Counter0 and Timer/Counter1 Prescalers
- 18. PSC – Power Stage Controller
- 18.1 Features
- 18.2 Overview
- 18.3 Accessing 16-bit Registers
- 18.4 PSC Description
- 18.5 Functional Description
- 18.6 Update of Values
- 18.7 Overlap Protection
- 18.8 Signal Description
- 18.9 PSC Input
- 18.10 PSC Input Modes 001b to 10xb: Deactivate outputs without changing timing.
- 18.11 PSC Input Mode 11xb: Halt PSC and Wait for Software Action
- 18.12 Analog Synchronization
- 18.13 Interrupt Handling
- 18.14 PSC Clock Sources
- 18.15 Interrupts
- 18.16 Register Description
- 18.16.1 POC – PSC Output Configuration
- 18.16.2 PSYNC – PSC Synchro Configuration
- 18.16.3 POCRnSAH and POCRnSAL – PSC Output Compare SA Register
- 18.16.4 POCRnRAH and POCRnRAL – PSC Output Compare RA Register
- 18.16.5 POCRnSBH and POCRnSBL – PSCOutput Compare SB Register
- 18.16.6 POCRnRBH and POCRnRBL – PSC Output Compare RB Register
- 18.16.7 PCNF – PSC Configuration Register
- 18.16.8 PCTL – PSC Control Register
- 18.16.9 PMICn – PSC Module n Input Control Register
- 18.16.10 PSC Interrupt Mask Register – PIM
- 18.16.11 PIFR – PSC Interrupt Flag Register
- 19. SPI – Serial Peripheral Interface
- 20. CAN – Controller Area Network
- 20.1 Features
- 20.2 Overview
- 20.3 CAN Protocol
- 20.3.1 Principles
- 20.3.2 Message Formats
- 20.3.3 CAN Bit Timing
- 20.3.3.1 Bit Construction
- 20.3.3.2 Synchronization Segment
- 20.3.3.3 Propagation Time Segment
- 20.3.3.4 Phase Segment 1
- 20.3.3.5 Sample Point
- 20.3.3.6 Phase Segment 2
- 20.3.3.7 Information Processing Time
- 20.3.3.8 Bit Lengthening
- 20.3.3.9 Bit Shortening
- 20.3.3.10 Synchronization Jump Width
- 20.3.3.11 Programming the Sample Point
- 20.3.3.12 Synchronization
- 20.3.4 Arbitration
- 20.3.5 Errors
- 20.4 CAN Controller
- 20.5 CAN Channel
- 20.6 Message Objects
- 20.7 CAN Timer
- 20.8 Error Management
- 20.9 Interrupts
- 20.10 Register Description
- 20.10.1 CANGCON – CAN General Control Register
- 20.10.2 CANGSTA – CAN General Status Register
- 20.10.3 CANGIT – CAN General Interrupt Register
- 20.10.4 CANGIE – CAN General Interrupt Enable Register
- 20.10.5 CANEN2 and CANEN1 – CAN Enable MOb Registers
- 20.10.6 CANIE2 and CANIE1 – CAN Enable Interrupt MOb Registers
- 20.10.7 CANSIT2 and CANSIT1 – CAN Status Interrupt MOb Registers
- 20.10.8 CANBT1 – CAN Bit Timing Register 1
- 20.10.9 CANBT2 – CAN Bit Timing Register 2
- 20.10.10 CANBT3 – CAN Bit Timing Register 3
- 20.10.11 CANTCON – CAN Timer Control Register
- 20.10.12 CANTIML and CANTIMH – CAN Timer Registers
- 20.10.13 CANTTCL and CANTTCH – CAN TTC Timer Registers
- 20.10.14 CANTEC – CAN Transmit Error Counter Register
- 20.10.15 CANREC – CAN Receive Error Counter Register
- 20.10.16 CANHPMOB – CAN Highest Priority MOb Register
- 20.10.17 CANPAGE – CAN Page MOb Register
- 20.11 MOb Registers
- 20.11.1 CANSTMOB – CAN MOb Status Register
- 20.11.2 CANCDMOB – CAN MOb Control and DLC Register
- 20.11.3 CANIDT1, CANIDT2, CANIDT3, and CANIDT4 – CAN Identifier Tag Registers
- 20.11.4 CANIDM1, CANIDM2, CANIDM3, and CANIDM4 – CAN Identifier Mask Registers
- 20.11.5 CANSTML and CANSTMH – CAN Time Stamp Registers
- 20.11.6 CANMSG – CAN Data Message Register
- 20.12 Examples of CAN Baud Rate Setting
- 21. LIN / UART - Local Interconnect Network Controller or UART
- 21.1 Features
- 21.2 Overview
- 21.3 LIN Protocol
- 21.4 LIN / UART Controller
- 21.5 LIN / UART Description
- 21.5.1 Reset
- 21.5.2 Clock
- 21.5.3 LIN Protocol Selection
- 21.5.4 Configuration
- 21.5.5 Busy Signal
- 21.5.6 Bit Timing
- 21.5.7 Data Length
- 21.5.8 xxOK Flags
- 21.5.9 xxERR Flags
- 21.5.10 Frame Time Out
- 21.5.11 Break-in-data
- 21.5.12 Checksum
- 21.5.13 Interrupts
- 21.5.14 Message Filtering
- 21.5.15 Data Management
- 21.5.16 OCD Support
- 21.6 Register Description
- 21.6.1 LINCR – LIN Control Register
- 21.6.2 LINSIR – LIN Status and Interrupt Register
- 21.6.3 LINENIR – LIN Enable Interrupt Register
- 21.6.4 LINERR – LIN Error Register
- 21.6.5 LINBTR – LIN Bit Timing Register
- 21.6.6 LINBRR – LIN Baud Rate Register
- 21.6.7 LINDLR – LIN Data Length Register
- 21.6.8 LINIDR – LIN Identifier Register
- 21.6.9 LINSEL – LIN Data Buffer Selection Register
- 21.6.10 LINDAT – LIN Data Register
- 22. ADC – Analog to Digital Converter
- 22.1 Features
- 22.2 Operation
- 22.3 Starting a Conversion
- 22.4 Prescaling and Conversion Timing
- 22.5 Changing Channel or Reference Selection
- 22.6 ADC Noise Canceler
- 22.7 ADC Conversion Result
- 22.8 Temperature Measurement
- 22.9 Amplifier
- 22.10 Register Description
- 22.10.1 ADMUX – ADC Multiplexer Register
- 22.10.2 Bit 4: 0 – MUX[4:0]: ADC Channel Selection Bits
- 22.10.3 ADCSRA – ADC Control and Status Register A
- 22.10.4 ADCSRB – ADC Control and Status Register B
- 22.10.5 ADCH and ADCL – ADC Result Data Registers
- 22.10.6 DIDR0 – Digital Input Disable Register 0
- 22.10.7 DIDR1 – Digital Input Disable Register 1
- 22.10.8 AMP0CSR – Amplifier 0 Control and Status register
- 22.10.9 AMP1CSR – Amplifier 1 Control and Status register
- 22.10.10 AMP2CSR – Amplifier 2 Control and Status register
- 23. ISRC - Current Source
- 24. AC – Analog Comparator
- 24.1 Features
- 24.2 Overview
- 24.3 Use of ADC Amplifiers
- 24.4 Register Description
- 24.4.1 AC0CON – Analog Comparator 0 Control Register
- 24.4.2 AC1CON – Analog Comparator 1Control Register
- 24.4.3 AC2CON – Analog Comparator 2 Control Register
- 24.4.4 AC3CON – Analog Comparator 3 Control Register
- 24.4.5 ACSR – Analog Comparator Status Register
- 24.4.6 DIDR0 – Digital Input Disable Register 0
- 24.4.7 DIDR1 – Digital Input Disable Register 1
- 25. DAC – Digital to Analog Converter
- 26. debugWIRE On-chip Debug System
- 27. Boot Loader Support – Read-While-Write Self-Programming
- 27.1 Overview
- 27.2 Application and Boot Loader Flash Sections
- 27.3 Read-While-Write and No Read-While-Write Flash Sections
- 27.4 Boot Loader Lock Bits
- 27.5 Entering the Boot Loader Program
- 27.6 Addressing the Flash During Self-Programming
- 27.7 Self-Programming the Flash
- 27.7.1 Performing Page Erase by SPM
- 27.7.2 Filling the Temporary Buffer (Page Loading)
- 27.7.3 Performing a Page Write
- 27.7.4 Using the SPM Interrupt
- 27.7.5 Consideration While Updating BLS
- 27.7.6 Prevent Reading the RWW Section During Self-Programming
- 27.7.7 Setting the Boot Loader Lock Bits by SPM
- 27.7.8 EEPROM Write Prevents Writing to SPMCSR
- 27.7.9 Reading the Fuse and Lock Bits from Software
- 27.7.10 Reading the Signature Row from Software
- 27.7.11 Preventing Flash Corruption
- 27.7.12 Programming Time for Flash when Using SPM
- 27.7.13 Simple Assembly Code Example for a Boot Loader
- 27.7.14 ATmega16M1 - 16K - Flash Boot Loader Parameters
- 27.7.15 ATmega32M1 - 32K - Flash Boot Loader Parameters
- 27.7.16 ATmega64M1 - 64K - Flash Boot Loader Parameters
- 27.8 Register Description
- 28. Memory Programming
- 28.1 Program And Data Memory Lock Bits
- 28.2 Fuse Bits
- 28.3 PSC Output Behavior During Reset
- 28.4 Signature Bytes
- 28.5 Calibration Byte
- 28.6 Page Size
- 28.7 Parallel Programming Parameters, Pin Mapping, and Commands
- 28.8 Serial Programming Pin Mapping
- 28.9 Parallel Programming
- 28.9.1 Enter Programming Mode
- 28.9.2 Considerations for Efficient Programming
- 28.9.3 Chip Erase
- 28.9.4 Programming the Flash
- 28.9.5 Programming the EEPROM
- 28.9.6 Reading the Flash
- 28.9.7 Reading the EEPROM
- 28.9.8 Programming the Fuse Low Bits
- 28.9.9 Programming the Fuse High Bits
- 28.9.10 Programming the Extended Fuse Bits
- 28.9.11 Programming the Lock Bits
- 28.9.12 Reading the Fuse and Lock Bits
- 28.9.13 Reading the Signature Bytes
- 28.9.14 Reading the Calibration Byte
- 28.9.15 Parallel Programming Characteristics
- 28.10 Serial Downloading
- 29. Electrical Characteristics
- 30. Typical Characteristics – TBD
- 31. Register Summary
- 32. Instruction Set Summary
- 33. Errata
- 34. Ordering Information
- 35. Packaging Information
- 36. Datasheet Revision History
- Table of Contents
159
8209A–AVR–08/09
ATmega16M1/32M1/64M1
19.3 SS Pin Functionality
19.3.1 Slave Mode
When the SPI is configured as a Slave, the Slave Select (SS)
pin is always input. When SS is
held low, the SPI is activated, and MISO becomes an output if configured so by the user. All
other pins are inputs. When SS
is driven high, all pins are inputs, and the SPI is passive, which
means that it will not receive incoming data. Note that the SPI logic will be reset once the SS
pin
is driven high.
The SS
pin is useful for packet/byte synchronization to keep the slave bit counter synchronous
with the master clock generator. When the SS
pin is driven high, the SPI slave will immediately
reset the send and receive logic, and drop any partially received data in the Shift Register.
19.3.2 Master Mode
When the SPI is configured as a Master (MSTR in SPCR is set), the user can determine the
direction of the SS
pin.
If SS
is configured as an output, the pin is a general output pin which does not affect the SPI
system. Typically, the pin will be driving the SS
pin of the SPI Slave.
If SS
is configured as an input, it must be held high to ensure Master SPI operation. If the SS pin
is driven low by peripheral circuitry when the SPI is configured as a Master with the SS
pin
defined as an input, the SPI system interprets this as another master selecting the SPI as a
slave and starting to send data to it. To avoid bus contention, the SPI system takes the following
actions:
1. The MSTR bit in SPCR is cleared and the SPI system becomes a Slave. As a result of
the SPI becoming a Slave, the MOSI and SCK pins become inputs.
2. The SPIF flag in SPSR is set, and if the SPI interrupt is enabled, and the I-bit in SREG
is set, the interrupt routine will be executed.
Thus, when interrupt-driven SPI transmission is used in Master mode, and there exists a possi-
bility that SS
is driven low, the interrupt should always check that the MSTR bit is still set. If the
MSTR bit has been cleared by a slave select, it must be set by the user to re-enable SPI Master
mode.
19.4 Data Modes
There are four combinations of SCK phase and polarity with respect to serial data, which are
determined by control bits CPHA and CPOL. The SPI data transfer formats are shown in Figure
19-3 and Figure 19-4. Data bits are shifted out and latched in on opposite edges of the SCK sig-
nal, ensuring sufficient time for data signals to stabilize. This is clearly seen by summarizing
Table 19-3 and Table 19-4, as done below:
Table 19-2. CPOL Functionality
Leading Edge Trailing eDge SPI Mode
CPOL=0, CPHA=0 Sample (Rising) Setup (Falling) 0
CPOL=0, CPHA=1 Setup (Rising) Sample (Falling) 1
CPOL=1, CPHA=0 Sample (Falling) Setup (Rising) 2
CPOL=1, CPHA=1 Setup (Falling) Sample (Rising) 3