Atmel ATmega8535L - About Code Examples

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ATmega8535(L)

2502K–AVR–10/06

About Code

Examples

This documentation contains simple code examples that briefly show how to use various

parts of the device. These code examples assume that the part specific header file is

included before compilation. Be aware that not all C compiler vendors include bit defini-

tions in the header files and interrupt handling in C is compiler dependent. Please

confirm with the C Compiler documentation for more details.

Main Page

Features1
Pin Configurations2
- Disclaimer2
Overview3
- Block Diagram3
- AT90S8535 Compatibility4
  - AT90S8535 Compatibility Mode4
- Pin Descriptions5
Resources6
About Code Examples7
AVR CPU Core8
- Introduction8
- Architectural Overview8
- ALU - Arithmetic Logic Unit9
- Status Register10
- General Purpose Register File11
  - The X-register, Y-register, and Z-register12
- Stack Pointer12
- Instruction Execution Timing13
- Reset and Interrupt Handling13
  - Interrupt Response Time15
AVR ATmega8535 Memories16
- In-System Reprogrammable Flash Program Memory16
- SRAM Data Memory17
  - Data Memory Access Times18
- EEPROM Data Memory18
- I/O Memory23
System Clock and Clock Options24
- Clock Systems and their Distribution24
- Clock Sources25
- Default Clock Source25
- Crystal Oscillator25
- Low-frequency Crystal Oscillator28
- External RC Oscillator28
- Calibrated Internal RC Oscillator29
  - Oscillator Calibration Register - OSCCAL30
- External Clock31
- Timer/Counter Oscillator31
Power Management and Sleep Modes32
- MCU Control Register - MCUCR32
- Idle Mode33
- ADC Noise Reduction Mode33
- Power-down Mode33
- Power-save Mode33
- Standby Mode34
- Extended Standby Mode34
- Minimizing Power Consumption35
System Control and Reset36
- Resetting the AVR36
- Reset Sources36
- Power-on Reset38
- External Reset39
- Brown-out Detection39
- Watchdog Reset40
- MCU Control and Status Register - MCUCSR40
- Internal Voltage Reference41
  - Voltage Reference Enable Signals and Start-up Time41
- Watchdog Timer41
  - Watchdog Timer Control Register - WDTCR42
- Timed Sequences for Changing the Configuration of the Watchdog Timer45
Interrupts46
- Interrupt Vectors in ATmega853546
  - Moving Interrupts Between Application and Boot Space49
  - General Interrupt Control Register - GICR49
I/O-Ports51
- Introduction51
- Ports as General Digital I/O52
- Alternate Port Functions57
- Register Description for I/O-Ports66
External Interrupts68
- MCU Control Register - MCUCR68
- MCU Control and Status Register - MCUCSR69
- General Interrupt Control Register - GICR69
- General Interrupt Flag Register - GIFR70
8-bit Timer/Counter0 with PWM71
- Overview71
  - Registers71
  - Definitions72
- Timer/Counter Clock Sources72
- Counter Unit72
- Output Compare Unit73
- Compare Match Output Unit75
  - Compare Output Mode and Waveform Generation75
- Modes of Operation76
- Timer/Counter Timing Diagrams80
- 8-bit Timer/Counter Register Description83
Timer/Counter0 and Timer/Counter1 Prescalers87
- Internal Clock Source87
- Prescaler Reset87
- External Clock Source87
- Special Function IO Register - SFIOR88
16-bit Timer/Counter189
- Overview89
- Accessing 16-bit Registers92
  - Re-using the Temporary High Byte Register94
- Timer/Counter Clock Sources95
- Counter Unit95
- Input Capture Unit96
- Output Compare Units98
- Compare Match Output Unit100
  - Compare Output Mode and Waveform Generation100
- Modes of Operation101
- Timer/Counter Timing Diagrams108
- 16-bit Timer/Counter Register Description110
8-bit Timer/Counter2 with PWM and Asynchronous Operation117
- Overview117
  - Registers118
  - Definitions118
- Timer/Counter Clock Sources118
- Counter Unit119
- Output Compare Unit119
- Compare Match Output Unit121
  - Compare Output Mode and Waveform Generation121
- Modes of Operation122
- Timer/Counter Timing Diagrams126
- 8-bit Timer/Counter Register Description128
- Asynchronous Operation of the Timer/Counter131
- Timer/Counter Prescaler134
  - Special Function IO Register - SFIOR135
Serial Peripheral Interface - SPI136
- SS Pin Functionality141
- Data Modes144
USART145
- Overview145
  - AVR USART vs. AVR UART - Compatibility146
- Clock Generation146
- Frame Formats149
  - Parity Bit Calculation150
- USART Initialization150
- Data Transmission - The USART Transmitter152
- Data Reception - The USART Receiver155
- Asynchronous Data Reception158
- Multi-processor Communication Mode162
  - Using MPCM162
- Accessing UBRRH/UCSRC Registers163
  - Write Access163
  - Read Access164
- USART Register Description164
- Examples of Baud Rate Setting170
Two-wire Serial Interface174
- Features174
- Two-wire Serial Interface Bus Definition174
  - TWI Terminology174
  - Electrical Interconnection175
- Data Transfer and Frame Format175
- Multi-master Bus Systems, Arbitration and Synchronization177
- Overview of the TWI Module179
- TWI Register Description181
- Using the TWI185
- Transmission Modes188
- Multi-master Systems and Arbitration201
Analog Comparator203
- Special Function IO Register - SFIOR203
- Analog Comparator Control and Status Register - ACSR203
- Analog Comparator Multiplexed Input205
Analog-to-Digital Converter206
- Features206
- Operation207
- Starting a Conversion208
- Prescaling and Conversion Timing209
  - Differential Gain Channels212
- Changing Channel or Reference Selection212
  - ADC Input Channels213
  - ADC Voltage Reference213
- ADC Noise Canceler214
- ADC Conversion Result218
Boot Loader Support - Read-While-Write Self-Programming224
- Boot Loader Features224
- Application and Boot Loader Flash Sections224
  - Application Section224
  - BLS - Boot Loader Section224
- Read-While-Write and No Read-While-Write Flash Sections224
  - RWW - Read-While-Write Section225
  - NRWW - No Read-While-Write Section225
- Boot Loader Lock Bits226
- Entering the Boot Loader Program227
  - Store Program Memory Control Register - SPMCR228
- Addressing the Flash during Self- Programming229
- Self-Programming the Flash230
Memory Programming237
- Program And Data Memory Lock Bits237
- Fuse Bits238
  - Latching of Fuses239
- Signature Bytes239
- Calibration Byte239
- Parallel Programming Parameters, Pin Mapping, and Commands240
  - Signal Names240
- Parallel Programming242
- Serial Downloading251
Electrical Characteristics255
- Absolute Maximum Ratings*255
- DC Characteristics255
- External Clock Drive Waveforms258
- External Clock Drive258
- Two-wire Serial Interface Characteristics259
- SPI Timing Characteristics261
- ADC Characteristics263
ATmega8535 Typical Characteristics266
- Active Supply Current266
- Idle Supply Current270
- Power-Down Supply Current273
- Power-Save Supply Current274
- Standby Supply Current275
- Pin Pullup279
- Pin Driver Strength281
- Pin Thresholds And Hysteresis283
- BOD Thresholds And Analog Comparator Offset286
- Internal Oscillator Speed288
- Current Consumption Of Peripheral Units295
- Current Consumption In Reset And Reset Pulsewidth297
Register Summary299
Instruction Set Summary301
Ordering Information304
Packaging Information306
- 44A306
- 40P6307
- 44J308
- 44M1-A309
Errata310
- ATmega8535 Rev. A and B310
Datasheet Revision History311
- Changes from Rev. 2502J- 08/06 to Rev. 2502K- 10/06311
- Changes from Rev. 2502I- 06/06 to Rev. 2502J- 08/06311
- Changes from Rev. 2502H- 04/06 to Rev. 2502I- 06/06311
- Changes from Rev. 2502G- 04/05 to Rev. 2502H- 04/06311
- Changes from Rev. 2502F- 06/04 to Rev. 2502G- 04/05311
- Changes from Rev. 2502E-12/03 to Rev. 2502G-06/04311
- Changes from Rev. 2502E-12/03 to Rev. 2502F-06/04311
- Changes from Rev. 2502D-09/03 to Rev. 2502E-12/03311
- Changes from Rev. 2502C-04/03 to Rev. 2502D-09/03312
- Changes from Rev. 2502B-09/02 to Rev. 2502C-04/03312
- Changes from Rev. 2502A-06/02 to Rev. 2502B-09/02313
Table of Contents315

Atmel ATmega8535L - About Code Examples

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