User guide

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Table Of Contents

Features
Pin Configurations
- Disclaimer
Overview
- Block Diagram
- ATmega161 and ATmega162 Compatibility
  - ATmega161 Compatibility Mode
- Pin Descriptions
- About Code Examples
AVR CPU Core
- Introduction
- Architectural Overview
- ALU – Arithmetic Logic Unit
- Status Register
- General Purpose Register File
  - The X-register, Y-register, and Z-register
- Stack Pointer
- Instruction Execution Timing
- Reset and Interrupt Handling
  - Interrupt Response Time
AVR ATmega162 Memories
- In-System Reprogrammable Flash Program Memory
- SRAM Data Memory
  - Data Memory Access Times
- EEPROM Data Memory
- I/O Memory
- External Memory Interface
- XMEM Register Description
System Clock and Clock Options
- Clock Systems and their Distribution
- Clock Sources
- Default Clock Source
- Crystal Oscillator
- Low-frequency Crystal Oscillator
- Calibrated Internal RC Oscillator
  - Oscillator Calibration Register – OSCCAL
- External Clock
- Clock output buffer
- Timer/Counter Oscillator
- System Clock Prescaler
  - Clock Prescale Register – CLKPR
Power Management and Sleep Modes
- MCU Control Register – MCUCR
- MCU Control and Status Register – MCUCSR
- Extended MCU Control Register – EMCUCR
- Idle Mode
- Power-down Mode
- Power-save Mode
- Standby Mode
- Extended Standby Mode
- Minimizing Power Consumption
System Control and Reset
- Resetting the AVR
- Reset Sources
- Power-on Reset
- External Reset
- Brown-out Detection
- Watchdog Reset
- MCU Control and Status Register – MCUCSR
- Internal Voltage Reference
  - Voltage Reference Enable Signals and Start-up Time
- Watchdog Timer
  - Watchdog Timer Control Register – WDTCR
- Timed Sequences for Changing the Configuration of the Watchdog Timer
Interrupts
- Interrupt Vectors in ATmega162
  - Moving Interrupts Between Application and Boot Space
  - General Interrupt Control Register – GICR
I/O-Ports
- Introduction
- Ports as General Digital I/O
- Alternate Port Functions
- Register Description for I/O-Ports
External Interrupts
- MCU Control Register – MCUCR
- Extended MCU Control Register – EMCUCR
- General Interrupt Control Register – GICR
- General Interrupt Flag Register – GIFR
- Pin Change Mask Register 1 – PCMSK1
- Pin Change Mask Register 0 – PCMSK0
8-bit Timer/Counter0 with PWM
- Overview
  - Registers
  - Definitions
- Timer/Counter Clock Sources
- Counter Unit
- Output Compare Unit
- Compare Match Output Unit
  - Compare Output Mode and Waveform Generation
- Modes of Operation
- Timer/Counter Timing Diagrams
- 8-bit Timer/Counter Register Description
Timer/Counter0, Timer/Counter1, and Timer/Counter3 Prescalers
- Internal Clock Source
- Prescaler Reset
- External Clock Source
- Special Function IO Register – SFIOR
16-bit Timer/Counter (Timer/Counter1 and Timer/Counter3)
- Restriction in ATmega161 Compatibility Mode
- Overview
- Accessing 16-bit Registers
  - Reusing the Temporary High Byte Register
- Timer/Counter Clock Sources
- Counter Unit
- Input Capture Unit
- Output Compare Units
- Compare Match Output Unit
  - Compare Output Mode and Waveform Generation
- Modes of Operation
- Timer/Counter Timing Diagrams
- 16-bit Timer/Counter Register Description
8-bit Timer/Counter2 with PWM and Asynchronous operation
- Overview
  - Registers
  - Definitions
- Timer/Counter Clock Sources
- Counter Unit
- Output Compare Unit
- Compare Match Output Unit
  - Compare Output Mode and Waveform Generation
- Modes of Operation
- Timer/Counter Timing Diagrams
- 8-bit Timer/Counter Register Description
- Asynchronous operation of the Timer/Counter
- Timer/Counter Prescaler
  - Special Function IO Register – SFIOR
Serial Peripheral Interface – SPI
- SS Pin Functionality
- Data Modes
USART
- Dual USART
  - AVR USART vs. AVR UART – Compatibility
- Clock Generation
- Frame Formats
  - Parity Bit Calculation
- USART Initialization
- Data Transmission – The USART Transmitter
- Data Reception – The USART Receiver
- Asynchronous Data Reception
- Multi-processor Communication Mode
  - Using MPCM
- Accessing UBRRH/ UCSRC Registers
  - Write Access
  - Read Access
- USART Register Description
- Examples of Baud Rate Setting
Analog Comparator
- Analog Comparator Control and Status Register – ACSR
JTAG Interface and On-chip Debug System
- Features
- Overview
- Test Access Port – TAP
- TAP Controller
- Using the Boundary- scan Chain
- Using the On-chip Debug system
- On-chip debug specific JTAG instructions
- On-chip Debug Related Register in I/O Memory
  - On-chip Debug Register – OCDR
- Using the JTAG Programming Capabilities
- Bibliography
IEEE 1149.1 (JTAG) Boundary-scan
- Features
- System Overview
- Data Registers
- Boundary-scan Specific JTAG Instructions
- Boundary-scan Chain
- ATmega162 Boundary- scan Order
- Boundary-scan Description Language Files
Boot Loader Support – Read-While-Write Self-programming
- Features
- Application and Boot Loader Flash Sections
  - Application Section
  - BLS – Boot Loader Section
- Read-While-Write and No Read-While-Write Flash Sections
  - RWW – Read-While-Write Section
  - NRWW – No Read-While-Write Section
- Boot Loader Lock Bits
- Entering the Boot Loader Program
  - Store Program Memory Control Register – SPMCR
- Addressing the Flash During Self- programming
- Self-programming the Flash
Memory Programming
- Program And Data Memory Lock Bits
- Fuse Bits
  - Latching of Fuses
- Signature Bytes
- Calibration Byte
- Parallel Programming Parameters, Pin Mapping, and Commands
  - Signal Names
- Parallel Programming
- Serial Downloading
- SPI Serial Programming Pin Mapping
- Programming via the JTAG Interface
Electrical Characteristics
- Absolute Maximum Ratings*
- DC Characteristics
- External Clock Drive Waveforms
- External Clock Drive
- SPI Timing Characteristics
- External Data Memory Timing
ATmega162 Typical Characteristics
- Active Supply Current
- Idle Supply Current
- Power-down Supply Current
- Power-save Supply Current
- Standby Supply Current
- Pin Pull-up
- Pin Driver Strength
- Pin Thresholds and Hysteresis
- BOD Thresholds and Analog Comparator Offset
- Internal Oscillator Speed
- Current Consumption of Peripheral Units
- Current Consumption in Reset and Reset Pulsewidth
Register Summary
Instruction Set Summary
Ordering Information
Packaging Information
- 44A
- 40P6
- 44M1
Erratas
- ATmega162, all rev.
Datasheet Change Log for ATmega162
- Changes from Rev. 2513D-04/03 to Rev. 2513E-09/03
- Changes from Rev. 2513C-09/02 to Rev. 2513D-04/03
- Changes from Rev. 2513B-09/02 to Rev. 2513C-09/02
- Changes from Rev. 2513A-05/02 to Rev. 2513B-09/02
Table of Contents

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ATmega162/V

2513E–AVR–09/03

Figure 61. Output Compare Unit, Block Diagram

The OCR2 Register is double buffered when using any of the 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

OCR2 Compare Register to either top or bottom of the counting sequence. The synchro-

nization prevents the occurrence of odd-length, non-symmetrical PWM pulses, thereby

making the output glitch-free.

The OCR2 Register access may seem complex, but this is not case. When the double

buffering is enabled, the CPU has access to the OCR2 Buffer Register, and if double

buffering is disabled the CPU will access the OCR2 directly.

Force Output Compare In non-PWM waveform generation modes, the match output of the comparator can be

forced by writing a one to the Force Output Compare (FOC2) bit. Forcing Compare

Match will not set the OCF2 Flag or reload/clear the timer, but the OC2 pin will be

updated as if a real Compare Match had occurred (the COM21:0 bits settings define

whether the OC2 pin is set, cleared or toggled).

Compare Match Blocking by

TCNT2 Write

All CPU write operations to the TCNT2 Register will block any Compare Match that

occurs in the next timer clock cycle, even when the timer is stopped. This feature allows

OCR2 to be initialized to the same value as TCNT2 without triggering an interrupt when

the Timer/Counter clock is enabled.

Using the Output Compare

Unit

Since writing TCNT2 in any mode of operation will block all compare matches for one

timer clock cycle, there are risks involved when changing TCNT2 when using the output

compare channel, independently of whether the Timer/Counter is running or not. If the

value written to TCNT2 equals the OCR2 value, the Compare Match will be missed,

OCFn (Int.Req.)

= (8-bit Comparator )

OCRn

OCxy

DATA BUS

TCNTn

WGMn1:0

Waveform Generator

top

FOCn

COMn1:0

bottom