"easy" 6510 question

From: Francesco Messineo <*francesco.messineo_at_gmail.com*> Date: Fri, 7 Feb 2020 19:48:21 +0100 Message-ID: <CAESs-_wDMsx35vbg5aQG8HUf8f5sLOc+XvUD7FC01X-fD0c-og_at_mail.gmail.com> · francesco.messineo_at_gmail.com

Hi all,
I should know this, but I probably totally forgot it: what values are
the Data and DDR registers in a MOS6510 initialized to at power on? I
am quite sure their values aren't altered by a /RES low->high input,
but I can't find anywhere in the datasheet what are the power on
values of those two registers. They can't be random (right?) otherwise
 a C64 would not start properly most of the times.
Thanks in advance
Frank