Datasheet ATtiny13A. Complete (Microchip) - 10

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4.4 General Purpose Register File
The Register File is optimized for the AVR Enhanced RISC instruction set. In order to achieve the required performance and flexibility, the following input/output schemes are supported by the Register File: • One 8-bit output operand and one 8-bit result input • Two 8-bit output operands and one 8-bit result input • Two 8-bit output operands and one 16-bit result input • One 16-bit output operand and one 16-bit result input Figure 4-2 shows the structure of the 32 general purpose working registers in the CPU.
Figure 4-2.
AVR CPU General Purpose Working Registers
7 0 Addr. R0 0x00 R1 0x01 R2 0x02 … R13 0x0D General R14 0x0E Purpose R15 0x0F Working R16 0x10 Registers R17 0x11 … R26 0x1A X-register Low Byte R27 0x1B X-register High Byte R28 0x1C Y-register Low Byte R29 0x1D Y-register High Byte R30 0x1E Z-register Low Byte R31 0x1F Z-register High Byte
Most of the instructions operating on the Register File have direct access to all registers, and most of them are single cycle instructions. As shown in Figure 4-2 on page 10, each register is also assigned a Data memory address, mapping them directly into the first 32 locations of the user Data Space. Although not being physically implemented as SRAM locations, this memory organization provides great flexibility in access of the registers, as the X-, Y- and Z-pointer registers can be set to index any register in the file.
4.4.1 The X-register, Y-register, and Z-register
The registers R26..R31 have some added functions to their general purpose usage. These reg- isters are 16-bit address pointers for indirect addressing of the data space. The three indirect address registers X, Y, and Z are defined as described in Figure 4-3 on page 11.
10 ATtiny13A
8126F–AVR–05/12 Document Outline Features 1. Pin Configurations 1.1 Pin Description 1.1.1 VCC 1.1.2 GND 1.1.3 Port B (PB5:PB0) 1.1.4 RESET 2. Overview 2.1 Block Diagram 3. About 3.1 Resources 3.2 Code Examples 3.3 Data Retention 4. CPU Core 4.1 Architectural Overview 4.2 ALU – Arithmetic Logic Unit 4.3 Status Register 4.3.1 SREG – Status Register 4.4 General Purpose Register File 4.4.1 The X-register, Y-register, and Z-register 4.5 Stack Pointer 4.5.1 SPL – Stack Pointer Low 4.6 Instruction Execution Timing 4.7 Reset and Interrupt Handling 4.7.1 Interrupt Response Time 5. Memories 5.1 In-System Reprogrammable Flash Program Memory 5.2 SRAM Data Memory 5.2.1 Data Memory Access Times 5.3 EEPROM Data Memory 5.3.1 EEPROM Read/Write Access 5.3.2 Atomic Byte Programming 5.3.3 Split Byte Programming 5.3.4 Erase 5.3.5 Write 5.3.6 Preventing EEPROM Corruption 5.4 I/O Memory 5.5 Register Description 5.5.1 EEARL – EEPROM Address Register 5.5.2 EEDR – EEPROM Data Register 5.5.3 EECR – EEPROM Control Register 6. System Clock and Clock Options 6.1 Clock Systems and their Distribution 6.1.1 CPU Clock – clkCPU 6.1.2 I/O Clock – clkI/O 6.1.3 Flash Clock – clkFLASH 6.1.4 ADC Clock – clkADC 6.2 Clock Sources 6.2.1 External Clock 6.2.2 Calibrated Internal 4.8/9.6 MHz Oscillator 6.2.3 Internal 128 kHz Oscillator 6.2.4 Default Clock Source 6.3 System Clock Prescaler 6.3.1 Switching Time 6.4 Register Description 6.4.1 OSCCAL – Oscillator Calibration Register 6.4.2 CLKPR – Clock Prescale Register 7. Power Management and Sleep Modes 7.1 Sleep Modes 7.1.1 Idle Mode 7.1.2 ADC Noise Reduction Mode 7.1.3 Power-down Mode 7.2 Software BOD Disable 7.3 Power Reduction Register 7.4 Minimizing Power Consumption 7.4.1 Analog to Digital Converter 7.4.2 Analog Comparator 7.4.3 Brown-out Detector 7.4.4 Internal Voltage Reference 7.4.5 Watchdog Timer 7.4.6 Port Pins 7.5 Register Description 7.5.1 BODCR – Brown-Out Detector Control Register 7.5.2 MCUCR – MCU Control Register 7.5.3 PRR – Power Reduction Register 8. System Control and Reset 8.1 Resetting the AVR 8.2 Reset Sources 8.2.1 Power-on Reset 8.2.2 External Reset 8.2.3 Brown-out Detection 8.2.4 Watchdog Reset 8.3 Internal Voltage Reference 8.3.1 Voltage Reference Enable Signals and Start-up Time 8.4 Watchdog Timer 8.5 Register Description 8.5.1 MCUSR – MCU Status Register 8.5.2 WDTCR – Watchdog Timer Control Register 9. Interrupts 9.1 Interrupt Vectors 9.2 External Interrupts 9.2.1 Low Level Interrupt 9.2.2 Pin Change Interrupt Timing 9.3 Register Description 9.3.1 MCUCR – MCU Control Register 9.3.2 GIMSK – General Interrupt Mask Register 9.3.3 GIFR – General Interrupt Flag Register 9.3.4 PCMSK – Pin Change Mask Register 10. I/O Ports 10.1 Overview 10.2 Ports as General Digital I/O 10.2.1 Configuring the Pin 10.2.2 Toggling the Pin 10.2.3 Switching Between Input and Output 10.2.4 Reading the Pin Value 10.2.5 Digital Input Enable and Sleep Modes 10.2.6 Unconnected Pins 10.3 Alternate Port Functions 10.3.1 Alternate Functions of Port B 10.4 Register Description 10.4.1 MCUCR – MCU Control Register 10.4.2 PORTB – Port B Data Register 10.4.3 DDRB – Port B Data Direction Register 10.4.4 PINB – Port B Input Pins Address 11. 8-bit Timer/Counter0 with PWM 11.1 Features 11.2 Overview 11.2.1 Registers 11.2.2 Definitions 11.3 Timer/Counter Clock Sources 11.4 Counter Unit 11.5 Output Compare Unit 11.5.1 Force Output Compare 11.5.2 Compare Match Blocking by TCNT0 Write 11.5.3 Using the Output Compare Unit 11.6 Compare Match Output Unit 11.6.1 Compare Output Mode and Waveform Generation 11.7 Modes of Operation 11.7.1 Normal Mode 11.7.2 Clear Timer on Compare Match (CTC) Mode 11.7.3 Fast PWM Mode 11.7.4 Phase Correct PWM Mode 11.8 Timer/Counter Timing Diagrams 11.9 Register Description 11.9.1 TCCR0A – Timer/Counter Control Register A 11.9.2 TCCR0B – Timer/Counter Control Register B 11.9.3 TCNT0 – Timer/Counter Register 11.9.4 OCR0A – Output Compare Register A 11.9.5 OCR0B – Output Compare Register B 11.9.6 TIMSK0 – Timer/Counter Interrupt Mask Register 11.9.7 TIFR0 – Timer/Counter 0 Interrupt Flag Register 12. Timer/Counter Prescaler 12.1 Overview 12.2 Prescaler Reset 12.3 External Clock Source 12.4 Register Description. 12.4.1 GTCCR – General Timer/Counter Control Register 13. Analog Comparator 13.1 Analog Comparator Multiplexed Input 13.2 Register Description 13.2.1 ADCSRB – ADC Control and Status Register 13.2.2 ACSR– Analog Comparator Control and Status Register 13.2.3 DIDR0 – Digital Input Disable Register 0 14. Analog to Digital Converter 14.1 Features 14.2 Overview 14.3 Operation 14.4 Starting a Conversion 14.5 Prescaling and Conversion Timing 14.6 Changing Channel or Reference Selection 14.6.1 ADC Input Channels 14.6.2 ADC Voltage Reference 14.7 ADC Noise Canceler 14.8 Analog Input Circuitry 14.9 Analog Noise Canceling Techniques 14.10 ADC Accuracy Definitions 14.11 ADC Conversion Result 14.12 Register Description 14.12.1 ADMUX – ADC Multiplexer Selection Register 14.12.2 ADCSRA – ADC Control and Status Register A 14.12.3 ADCL and ADCH – The ADC Data Register 14.12.3.1 ADLAR = 0 14.12.3.2 ADLAR = 1 14.12.4 ADCSRB – ADC Control and Status Register B 14.12.5 DIDR0 – Digital Input Disable Register 0 15. debugWIRE On-chip Debug System 15.1 Features 15.2 Overview 15.3 Physical Interface 15.4 Software Break Points 15.5 Limitations of debugWIRE 15.6 Register Description 15.6.1 DWDR –debugWire Data Register 16. Self-Programming the Flash 16.1 Performing Page Erase by SPM 16.2 Filling the Temporary Buffer (Page Loading) 16.3 Performing a Page Write 16.4 Addressing the Flash During Self-Programming 16.5 EEPROM Write Prevents Writing to SPMCSR 16.6 Reading Fuse and Lock Bits from Firmware 16.6.1 Reading Lock Bits from Firmware 16.6.2 Reading Fuse Bits from Firmware 16.7 Preventing Flash Corruption 16.8 Programming Time for Flash when Using SPM 16.9 Register Description 16.9.1 SPMCSR – Store Program Memory Control and Status Register 17. Memory Programming 17.1 Program And Data Memory Lock Bits 17.2 Fuse Bytes 17.2.1 Latching of Fuses 17.3 Calibration Bytes 17.4 Signature Bytes 17.5 Page Size 17.6 Serial Programming 17.6.1 Serial Programming Algorithm 17.6.2 Serial Programming Instruction set 17.7 High-Voltage Serial Programming 17.7.1 High-Voltage Serial Programming Algorithm 17.7.2 High-Voltage Serial Programming Instruction set 17.8 Considerations for Efficient Programming 17.8.1 Chip Erase 17.8.2 Programming the Flash 17.8.3 Programming the EEPROM 17.8.4 Reading the Flash 17.8.5 Reading the EEPROM 17.8.6 Programming and Reading the Fuse and Lock Bits 17.8.7 Reading the Signature Bytes and Calibration Byte 17.8.8 Power-off sequence 18. Electrical Characteristics 18.1 Absolute Maximum Ratings* 18.2 DC Characteristics 18.3 Speed 18.4 Clock Characteristics 18.4.1 Calibrated Internal RC Oscillator Accuracy 18.4.2 External Clock Drive 18.5 System and Reset Characteristics 18.5.1 Enhanced Power-On Reset 18.5.2 Brown-Out Detection 18.6 Analog Comparator Characteristics 18.7 ADC Characteristics 18.8 Serial Programming Characteristics 18.9 High-voltage Serial Programming Characteristics 19. Typical Characteristics 19.1 Supply Current of I/O Modules 19.1.1 Example 19.2 Current Consumption in Active Mode 19.3 Current Consumption in Idle Mode 19.4 Current Consumption in Power-down Mode 19.5 Current Consumption in Reset 19.6 Current Consumption of Peripheral Units 19.7 Pull-up Resistors 19.8 Output Driver Strength (Low Power Pins) 19.9 Output Driver Strength (Regular Pins) 19.10 Input Thresholds and Hysteresis (for I/O Ports) 19.11 BOD, Bandgap and Reset 19.12 Internal Oscillator Speed 20. Register Summary 21. Instruction Set Summary 22. Ordering Information 23. Packaging Information 23.1 8P3 23.2 8S2 23.3 8S1 23.4 20M1 23.5 10M1 24. Errata 24.1 ATtiny13A Rev. G – H 24.2 ATtiny13A Rev. E – F 24.3 ATtiny13 Rev. A – D 25. Datasheet Revision History 25.1 Rev. 8126F – 05/12 25.2 Rev. 8126E – 07/10 25.3 Rev. 8126D – 11/09 25.4 Rev. 8126C – 09/09 25.5 Rev. 8126B – 11/08 25.6 Rev. 8126A – 05/08 Table of Contents