3

ATtiny28L/V

1062FS–AVR–07/06

rupt on low-level input feature enables the ATtiny28 to be highly responsive to external

events, still featuring the lowest power consumption while in the power-down modes.

The device is manufactured using Atmel’s high-density, nonvolatile memory technology.

By combining an enhanced RISC 8-bit CPU with Flash on a monolithic chip, the Atmel

ATtiny28 is a powerful microcontroller that provides a highly flexible and cost-effective

solution to many embedded control applications. The ATtiny28 AVR is supported with a

full suite of program and system development tools including: macro assemblers, pro-

gram debugger/simulators, in-circuit emulators and evaluation kits.

Pin Descriptions

VCC

Supply voltage pin.

GND

Ground pin.

Port A (PA3..PA0)

Port A is a 4-bit I/O port. PA2 is output-only and can be used as a high-current LED

driver. At V

bi-directional I/O pins with internal pull-ups (selected for each bit). The port pins are tri-

stated when a reset condition becomes active, even if the clock is not running.

Port B (PB7..PB0)

Port B is an 8-bit input port with internal pull-ups (selected for all Port B pins). Port B

pins that are externally pulled low will source current if the pull-ups are activated.

Port B also serves the functions of various special features of the ATtiny28 as listed on

page 27. If any of the special features are enabled, the pull-up(s) on the corresponding

pin(s) is automatically disabled. The port pins are tri-stated when a reset condition

becomes active, even if the clock is not running.

Port D (PD7..PD0)

Port D is an 8-bit I/O port. Port pins can provide internal pull-up resistors (selected for

each bit). The port pins are tri-stated when a reset condition becomes active, even if the

clock is not running.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

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.