I'm a developer and I'm using a ATMEL UC3A0512 micro.
I have found a big problem at the start up.
When you power up the micro and the VCC 3.3V go up you can found on the I/O lines some spikes.
The presence of this spikes depend from the slew rate of the power up, and depend from the delay between VCC and VCC_IO.
If the daley is = 0 the the presence of the spikes is guaranteed, if the delay is about 5 mS this spikes occours some times (1 times on 3).
If the delay is more then 5 mS the micro some time do not start and the power consumption are more then 200 mA.
THIS SPIKES OCCOURS BEFORE THE RAISE UP OF THE RESET SIGNAL WHEN THE CODE IS NOT STILL STARTED
This problem depend from internal power management of the micro (ATMEL said this).
After one years of discussion with AMEL, they admitted that there is a problem.
This is the answer of ATMEL:
We regret the delays in communication.
We had to get the confirmation from our internal team on issue.
The internal team has confirmed the issue and we were able to reproduce it in lab.
The workaround is to introduce a delay for VDDIO. We have tested it and it is removing the spike in GPIO pins.
In our tests, using external RC for VCC didn't work as expected(spike level was reduced but didnt remove it). We would recommend to use the workaround proposed.
Sorry for the inconvenience caused.
Ram Raja Kumar
Atmel Technical Support Team "
After this I ask to ATMEL if is possible a new release of the micro, but the new answer of ATMEL is that the micro is OK and suggest me to put same filter on the I/O.
I' hope that this message go in all corner of the world.
PS. I have changed the micro now !