ChipRef

Chip Ref allows you to check the pinouts and characteristics of many common ICs,
including:

ATmega series chips as used in arduino (ATMega128, AtMega328)
ATTiny series chips as used in trinket ( ATTiny85 chip)

Includes external links to PDF datasheets

Internet access only required for datasheets, pinouts etc are inside the app.

Twitter: @mikered