attiny22l ATMEL Corporation, attiny22l Datasheet - Page 3

• Manufacturer Part Number: attiny22l
• Description: 8-bit Microcontroller With 2k Bytes Of In-system Programmable Flash - Atmel Corporation
• Manufacturer: ATMEL Corporation

ATtiny22L
The ATtiny22L 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 ATtiny22L is a powerful microcontroller that provides a highly flexible and cost effec-
tive solution to many embedded control applications.
The ATtiny22L 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 ATtiny22L
VCC
Supply voltage pin.
GND
Ground pin.
Port B (PB4..PB0)
Port B is a 5-bit bi-directional I/O port with internal pull-up resistors. The Port B output buffers can sink 20 mA. As inputs,
Port B pins that are externally pulled low, will source current if the pull-up resistors are activated.
Port B also serves the functions of various special features.
Port pins can provide internal pull-up resistors (selected for each bit). The port B pins are tri-stated when a reset condition
becomes active.
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 Source
The ATtiny22L is clocked by an on-chip RC oscillator. This RC oscillator runs at a nominal frequency of 1 MHz (VCC = 5V).
Architectural Overview
The fast-access register file concept contains 32 x 8-bit general purpose working registers with a single clock cycle access
time. This means that during one single clock cycle, one arithmetic logic unit (ALU) operation is executed. Two operands
are output from the register file, the operation is executed, and the result is stored back in the register file in one clock
cycle.
Six of the 32 registers can be used as three 16-bit indirect address register pointers for Data Space addressing enabling
efficient address calculations. One of the three address pointers is also used as the address pointer for the constant table
look up function. These added function registers are the 16-bit X-register, Y-register and Z-register.
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