In the compiler package WinAVR-20090313 the SRAM start address has a wrong value
of 0x100. In this case the variables are randomly allocated across the extended I/O
space 0x100 to 0x1FF. It causes an unpredictable behavior by random overwrite of
registers (see also

"JTAG interface reads wrong data" on page 514

and

"DVREG_EXT

bit is not write-protected" on page 514

Problem Fix/Workaround

Use the linker option -Wl,--section-start=.data=0x800200

38.5 Detailed errata description

38.5.1 Power-Chain turns off when power supply drops below 1.6V

If the voltage of the pins DEVDD drops below 1.6V, the internal power chain turns off.
Some hardware settings (e.g. clock source) can alter their state unintentionally. Raising
the supply voltage above 1.8V again does not bring the circuit back to normal operation.
This condition can happen either by lowering the power supply voltage below 1.6V or
turn-off the supply source while other external devices are feeding DEVDD by the
internal ESD diodes of the IO stages (e.g. hardware debugger attached to the JTAG
interface) (2606).

If the power supply drops below 1.6V while being in Deep Sleep mode, the internal
power chain is not affected.

Problem Fix/Workaround

Turn on the Brown-Out Detector at any voltage level. The supply current in Deep Sleep
does not increase.