3.3.1 System Clock and Clock Options

A clarification for the “Clock Systems and Their Distribution” section has been made.

Figure “Clock Distribution” presents the different clock systems in the ATmega640/1280/1281/2560/2561 and their distribution. All of the clocks need not be active at a given time. The clocks to modules not being used can be halted using different sleep modes, as described in the ”Power management and Sleep Modes” section, to reduce the power consumption.

Figure “Clock Distribution” helps select an appropriate sleep mode.