Datasheet ATtiny22, ATtiny22L - Preliminary (Atmel) - 3

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ATtiny22/22L
The ATtiny22/L provides the following features: 2K bytes of In-System Programmable Flash, 128 bytes EEPROM, 128 bytes SRAM, five general purpose I/O lines, 32 general purpose working registers, an 8-bit timer/counter, internal and external interrupts, programmable Watchdog Timer with internal oscillator, an SPI serial port for Flash Memory download- ing and two software selectable power saving modes. The Idle Mode stops the CPU while allowing the SRAM, timer/counters, SPI port 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 device is manufactured using Atmel’s high density nonvolatile memory technology. The on-chip Flash allows the program memory to be reprogrammed in-system through an SPI serial interface. By combining an 8-bit RISC CPU with ISP Flash on a monolithic chip, the Atmel ATtiny22/L is a powerful microcontroller that provides a highly flexible and cost effec- tive solution to many embedded control applications. The ATtiny22/L AVR is supported with a full suite of program and system development tools including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators, and evaluation kits.
Pin Descriptions ATtiny22/L VCC
Supply voltage pin.
GND
Ground pin.
Port B (PB4..PB0)
Port B is a 5-bit bi-directional I/O port. Port pins can provide internal pull-up resistors (selected for each bit). When the device is clocked from an external clock source, PB3 is used as the clock input. The port B pins are tri-stated when a reset condition becomes active, even if the clock is not running.
RESET
Reset input. An external reset is generated by a low level on the RESET pin. Reset pulses longer than 50 ns will generate a reset, even if the clock is not running. Shorter pulses are not guaranteed to generate a reset.
CLOCK
Clock signal input in external clock mode.
Clock Options External Clock
The ATtiny22/L can be clocked by an external clock signal, as shown in Figure 2, or by the on-chip RC oscillator. This RC oscillator runs at a nominal frequency of 1 MHz (VCC = 5V). A fuse bit - RCEN - in the Flash memory selects the on-chip RC oscillator as the clock source when programmed (“0”). The ATtiny22/L is shipped with this bit programmed.
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Document Outline Features Description Block Diagram Pin Descriptions ATtiny22/L VCC GND Port B (PB4..PB0) RESET CLOCK Clock Options External Clock Architectural Overview General Purpose Register File X-Register, Y-Register, and Z-Register ALU - Arithmetic Logic Unit In-System Programmable Flash Program Memory EEPROM Data Memory SRAM Data Memory Program and Data Addressing Modes Register Direct, Single Register Rd Register Direct, Two Registers Rd and Rr I/O Direct Data Direct Data Indirect with Displacement Data Indirect Data Indirect With Pre-Decrement Data Indirect With Post-Increment Constant Addressing Using the LPM Instruction Indirect Program Addressing, IJMP and ICALL Relative Program Addressing, RJMP and RCALL Memory Access and Instruction Execution Timing I/O Memory Status Register - SREG Stack Pointer - SPL Reset and Interrupt Handling Reset Sources Power-On Reset External Reset Watchdog Reset MCU Status Register - MCUSR Interrupt Handling General Interrupt Mask Register - GIMSK General Interrupt Flag Register - GIFR Timer/Counter Interrupt Mask Register - TIMSK Timer/Counter Interrupt FLAG Register - TIFR External Interrupt Interrupt Response Time MCU Control Register - MCUCR Sleep Modes Idle Mode Power Down Mode Timer/Counter Timer/Counter Prescaler 8-Bit Timer/Counter0 Timer/Counter0 Control Register - TCCR0 Timer Counter 0 - TCNT0 Watchdog Timer Watchdog Timer Control Register - WDTCR EEPROM Read/Write Access EEPROM Address Register - EEAR EEPROM Data Register - EEDR EEPROM Control Register - EECR Prevent EEPROM Corruption I/O Port B Port B Data Register - PORTB Port B Data Direction Register - DDRB Port B Input Pins Address - PINB General Digital I/O Alternate Functions of Port B CLOCK - Port B, Bit 3 SCK/T0 - Port B, Bit 2 MISO - Port B, Bit 1 MOSI - Port B, Bit 0 Memory Programming Program and Data Memory Lock Bits Fuse Bits Signature Bytes Programming the Flash and EEPROM High-Voltage Serial Programming High-Voltage Serial Programming Algorithm High-Voltage Serial Programming Characteristics Low-Voltage Serial Downloading Low-Voltage Serial Programming Algorithm Data Polling EEPROM Data Polling Flash Low-Voltage Serial Programming Characteristics Electrical Characteristics Absolute Maximum Ratings* DC Characteristics External Clock Drive Waveforms External Clock Drive Typical characteristics Register Summary Instruction Set Summary (Continued) Ordering Information