7. General Information
7.1. Resources
A comprehensive set of development tools, application notes, and datasheets are available for download
on http://www.atmel.com/avr.
7.2. Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less than 1 PPM
over 20 years at 85°C.
7.3. About Code Examples
This documentation contains simple code examples that briefly show how to use various parts of the
device. These code examples assume that the part specific header file is included before compilation. Be
aware that not all C compiler vendors include bit definitions in the header files and interrupt handling in C
is compiler dependent. Confirm with the C compiler documentation for more details.
For I/O Registers located in extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”, and “SBI” instructions
must be replaced with instructions that allow access to extended I/O. Typically “LDS” and “STS”
combined with “SBRS”, “SBRC”, “SBR”, and “CBR”.
7.4. Capacitive Touch Sensing
7.4.1. QTouch Library
The Atmel
®
QTouch
®
Library provides a simple to use solution to realize touch sensitive interfaces on
most Atmel AVR
®
microcontrollers. The QTouch Library includes support for the Atmel QTouch and Atmel
QMatrix
®
acquisition methods.
Touch sensing can be added to any application by linking the appropriate Atmel QTouch Library for the
AVR Microcontroller. This is done by using a simple set of APIs to define the touch channels and sensors,
and then calling the touch sensing API’s to retrieve the channel information and determine the touch
sensor states.
The QTouch Library is FREE and downloadable from the Atmel website at the following location: http://
www.atmel.com/technologies/touch/. For implementation details and other information, refer to the Atmel
QTouch Library User Guide - also available for download from the Atmel website.
Atmel ATmega644PA [DATASHEET]
Atmel-42717C-ATmega644PA_Datasheet_Summary-10/2016
13
