Thank you both, Mario and Alan.

I checked errata for 30f4011 and discovered it has "lots" of "bugs", my
next micro will be a 33F or 33EP (I love 33EP256MU806 specs for a 64 pin
micro).

It is not possible to do AD conversions at 1 Msps due to bugs, max is 750
ksps.

After inspection of assembly output from my C compiler, I discovered it was
setting SAMC and ADCS in ADCON3 register at its maximum values (SAMC=3D1111=
1
"31 Tad" and ADCS=3D111111 "32 Tcy"). That was the reason of its slow speed=
..
Now, lowering this values I speeded it up a lot. I have to check for
integrity of data at that speed, but looks promissing and more acceptable.

I still have a lot of doubts, but the increase of speed makes me happy and
do not need to dig more into the question by the moment.

Thanks again.
--=20
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