Datasheet ATtiny28L, ATtiny28V (Atmel) - 2

Description
The ATtiny28 is a low-power CMOS 8-bit microcontroller based on the AVR RISC archi- tecture. By executing powerful instructions in a single clock cycle, the ATtiny28 achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to optimize power consumption versus processing speed. The AVR core combines a rich instruction set with 32 general-purpose working registers. All the 32 registers are directly con- nected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architec- ture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.
Block Diagram Figure 1.
The ATtiny28 Block Diagram VCC XTAL1 XTAL2 8-BIT DATA BUS INTERNAL CALIBRATED INTERNAL OSCILLATOR OSCILLATOR OSCILLATOR GND PROGRAM STACK WATCHDOG TIMING AND RESET COUNTER POINTER TIMER CONTROL PROGRAM HARDWARE MCU CONTROL FLASH STACK REGISTER INSTRUCTION TIMER/ GENERAL REGISTER COUNTER PURPOSE REGISTERS INSTRUCTION INTERRUPT DECODER Z UNIT CONTROL ALU LINES STATUS REGISTER HARDWARE MODULATOR PROGRAMMING LOGIC DATA REGISTER DATA REGISTER DATA DIR DATA REGISTER PORTA CONTROL + - PORTB PORTD REG. PORTD PORTA REGISTER ANALOG COMPARATOR PORTB PORTD PORTA The ATtiny28 provides the following features: 2K bytes of Flash, 11 general-purpose I/O lines, 8 input lines, a high-current LED driver, 32 general-purpose working registers, an 8-bit timer/counter, internal and external interrupts, programmable Watchdog Timer with internal oscillator and 2 software-selectable power-saving modes. The Idle Mode stops the CPU while allowing the timer/counter and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. The wake-up or inter-
2 ATtiny28L/V
1062F–AVR–07/06 Document Outline Features Pin Configurations Description Block Diagram Pin Descriptions VCC GND Port A (PA3..PA0) Port B (PB7..PB0) Port D (PD7..PD0) XTAL1 XTAL2 RESET Architectural Overview ALU - Arithmetic Logic Unit Subroutine and Interrupt Hardware Stack General-purpose Register File Status Register Status Register - SREG System Clock and Clock Options Internal RC Oscillator Calibrated Internal RC Oscillator Crystal Oscillator External Clock External RC Oscillator Register Description Oscillator Calibration Register - OSCCAL Memories I/O Memory Program and Data Addressing Modes Register Direct, Single Register Rd Register Indirect Register Direct, Two Registers Rd and Rr I/O Direct Relative Program Addressing, RJMP and RCALL Constant Addressing Using the LPM Instruction Memory Access and Instruction Execution Timing Flash Program Memory Sleep Modes Idle Mode Power-down Mode System Control and Reset Reset Sources Power-on Reset External Reset Watchdog Reset Register Description MCU Control and Status Register - MCUCS Interrupts Reset and Interrupt Interrupt Handling Interrupt Response Time External Interrupt Low-level Input Interrupt Register Description Interrupt Control Register - ICR Interrupt Flag Register - IFR I/O Ports Port A Port A as General Digital I/O Alternate Function of PA2 Port A Schematics Port B Port B as General Digital Input Alternate Functions of Port B Port B Schematics Port D Port D as General Digital I/O Register Description Port A Data Register - PORTA Port A Control Register - PACR Port A Input Pins Address - PINA Port B Input Pins Address - PINB Port D Data Register - PORTD Port D Data Direction Register - DDRD Port D Input Pins Address - PIND Timer/Counter0 Timer/Counter Prescaler Register Description Timer/Counter0 Control Register - TCCR0 Timer Counter 0 - TCNT0 Watchdog Timer Register Description Watchdog Timer Control Register - WDTCR Hardware Modulator Register Description Modulation Control Register - MODCR Analog Comparator Register Description Analog Comparator Control and Status Register - ACSR Memory Programming Program Memory Lock Bits Fuse Bits Signature Bytes Calibration Byte Programming the Flash Parallel Programming Signal Names Enter Programming Mode Chip Erase Programming the Flash Reading the Flash Programming the Fuse Bits Programming the Lock Bits Reading the Fuse and Lock Bits Reading the Signature Bytes and Calibration Byte Parallel Programming Characteristics Electrical Characteristics Absolute Maximum Ratings DC Characteristics External Clock Drive Waveforms External Clock Drive Typical Characteristics Register Summary Instruction Set Summary Ordering Information Packaging Information 32A 28P3 32M1-A Errata All revisions Datasheet Revision History Rev - 01/06G Rev - 01/06G Rev - 03/05F Table of Contents