[En-Nut-Discussion] power optimizations in idle thread

[Mustafa Yuecel]

> 2. disable ADC and buskeeper before entering sleep mode and re-enable
> these after wakeup:

I better refer to the MCU datasheet...

About disabling buskeeper:
http://www.btnode.ethz.ch/pub/uploads/Documentation/atmel_atmega128l.pdf,
page 27, 'Pull-up and Bus-keeper' section

About disabling ADC:
http://www.btnode.ethz.ch/pub/uploads/Documentation/atmel_atmega128l.pdf,
page 45, 'Analog to Digital Converter' section