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

Boot Loader Support

– Read-While-Write

Self-programming

The Boot Loader Support provides a real Read-While-Write Self-programming mecha-

nism for downloading and uploading program code by the MCU itself. This feature

allows flexible application software updates controlled by the MCU using a Flash-resi-

dent Boot Loader program. The Boot Loader program can use any available data

interface and associated protocol to read code and write (program) that code into the

Flash memory, or read the code from the program memory. The program code within

the Boot Loader section has the capability to write into the entire Flash, including the

Boot Loader memory. The Boot Loader can thus even modify itself, and it can also

erase itself from the code if the feature is not needed anymore. The size of the Boot

Loader memory is configurable with Fuses and the Boot Loader has two separate sets

of Boot Lock bits which can be set independently. This gives the user a unique flexibility

to select different levels of protection.

Features • Read-While-Write Self-programming

• Flexible Boot Memory Size

• High Security (Separate Boot Lock Bits for a Flexible Protection)

• Separate Fuse to Select Reset Vector

• Optimized Page

(1)

Size

• Code Efficient Algorithm

• Efficient Read-Modify-Write Support

Note: 1. A page is a section in the Flash consisting of several bytes (see Table 106 on page

235) used during programming. The page organization does not affect normal

operation.

Application and Boot

Loader Flash Sections

The Flash memory is organized in two main sections, the Application section and the

Boot Loader section (see Figure 94). The size of the different sections is configured by

the BOOTSZ Fuses as shown in Table 94 on page 228 and Figure 94. These two sec-

tions can have different level of protection since they have different sets of Lock bits.

Application Section The Application section is the section of the Flash that is used for storing the application

code. The protection level for the application section can be selected by the Application

Boot Lock bits (Boot Lock bits 0), see Table 90 on page 219. The Application section

can never store any Boot Loader code since the SPM instruction is disabled when exe-

cuted from the Application section.

BLS – Boot Loader Section While the Application section is used for storing the application code, the The Boot

Loader software must be located in the BLS since the SPM instruction can initiate a pro-

gramming when executing from the BLS only. The SPM instruction can access the

entire Flash, including the BLS itself. The protection level for the Boot Loader section

can be selected by the Boot Loader Lock bits (Boot Lock bits 1), see Table 91 on page

219.

Read-While-Write and No

Read-While-Write Flash

Sections

Whether the CPU supports Read-While-Write or if the CPU is halted during a Boot

Loader software update is dependent on which address that is being programmed. In

addition to the two sections that are configurable by the BOOTSZ Fuses as described

above, the Flash is also divided into two fixed sections, the Read-While-Write (RWW)

section and the No Read-While-Write (NRWW) section. The limit between the RWW-

and NRWW sections is given in Table 95 on page 228 and Figure 94 on page 218. The

main difference between the two sections is:

• When erasing or writing a page located inside the RWW section, the NRWW section

can be read during the operation.

• When erasing or writing a page located inside the NRWW section, the CPU is halted

during the entire operation.