2.3.15
PEN
This is a programming enable pin for the SPI Serial Programming mode. By holding this pin low during a Power-on
Reset, the device will enter the SPI Serial Programming mode. PEN is internally pulled high. The pullup is shown in
Figure 11-1 on page 49 and its value is given in Section 29.2 “DC Characteristics” on page 304. PEN has no func-
tion during normal operation.
3. Resources
A comprehensive set of development tools, application notes and datasheetsare available for download on
http://www.atmel.com/avr.
Note: 1.
4. 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 or 100 years at 25°C.
5. About Code Examples
This datasheet 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.
Please 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”.
6. Capacitive touch sensing
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 QTouch and QMatrix® acquisition methods.
Touch sensing can be added to any application by linking the appropriate Atmel QTouch Library for the AVR Micro-
controller. 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:
www.atmel.com/qtouchlibrary. For implementation details and other information, refer to the Atmel QTouch Library
User Guide - also available for download from the Atmel website.
ATmega64A [DATASHEET]
7
8160DS–AVR–02/2013
ATMEL [ ATMEL ]
