timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O
modules except Asynchronous Timer and ADC, to minimize switching noise during ADC conversions. In
Standby mode, the Crystal/Resonator Oscillator is running while the rest of the device is sleeping. This allows
very fast start-up combined with low power consumption. In Extended Standby mode, both the main Oscillator
and the Asynchronous Timer continue to run.
Atmel offers the QTouch® library for embedding capacitive touch buttons, sliders and wheels functionality into
AVR microcontrollers. The patented charge-transfer signal acquisition offers robust sensing and includes fully
debounced reporting of touch keys and includes Adjacent Key Suppression® (AKS™) technology for
unambiguous detection of key events. The easy-to-use QTouch Suite toolchain allows you to explore, develop
and debug your own touch applications.
The device is manufactured using Atmel’s high-density nonvolatile memory technology. The On-chip ISP Flash
allows the program memory to be reprogrammed in-system through an SPI serial interface, by a conventional
nonvolatile memory programmer, or by an On-chip Boot program running on the AVR core. The boot program
can use any interface to download the application program in the application Flash memory. Software in the
Boot Flash section will continue to run while the Application Flash section is updated, providing true Read-
While-Write operation. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on a
monolithic chip, the Atmel ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P is a powerful
microcontroller that provides a highly flexible and cost effective solution to many embedded control applications.
The ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P 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.
2.2 Comparison between ATmega164A, ATmega164PA, ATmega324A, ATmega324PA,
ATmega644A, ATmega644PA, ATmega1284 and ATmega1284P
Differences between ATmega164A, ATmega164PA, ATmega324A, ATmega324PA, ATmega644A,
ATmega644PA, ATmega1284 and ATmega1284P.
2.3 Pin Descriptions11
Digital supply voltage.