39.1.1 Rev. A
– Wrong device ID when using debugWire
– Power consumption in power save modes
– USART start-up functionality not working
– External capacitor on AREF pin
– Increased power consumption when using voltage reference other than AVCC
1.) Wrong device ID when using debugWire
The device ID returned using debugWire is incorrect.
Problem Fix/Workaround
None.
2.) Power consumption in power save modes
Power consumption in power save modes will be higher due to improper control of internal power management.
Problem Fix/Workaround
None.
3.) USART start-up functionality not working
While in power save modes, the USART start bit detection logic fails to wake up the device.
Problem Fix/Workaround
None.
4.) External capacitor on AREF pin
If an external capacitor is used on the analog reference pin (AREF), it should be equal to or larger than 100nF. Smaller capacitor value can make the AREF buffer unstable with large ringing which will reduce the accuracy of the ADC.
Problem Fix/Workaround
None.
5. ) Increased power consumption when using voltage reference other than AVCC
Power consumption is higher when using internal or external voltage reference that is not equal to AVCC. The increased current consumption will be the same for active and all sleep modes, but the largest impact will be in low power sleep modes.
Problem Fix/Workaround
Select AVCC as ADC voltage reference before entering sleep mode to avoid extra power consumption during sleep. If no internal or external reference to the ADC is used, an external pull-down resistor should be added to the AREF pin.