These days 20mA is a "high current" I/O. When you do the math on an 88-pin package, 20mA * N active outputs gets big pretty fast. The max total I/O current ca

These days 20mA is a "high current" I/O. When you do the math on an 88-pin package, 20mA * N active outputs gets big pretty fast. The max total I/O current can be found somewhere around page 987 of the data sheet... don't stop reading early... :) (edit: 88 I/O is a modest size microcontroller sort of chip)