Hello Ofir.
I believe the 8051 series is a good place to start There is lots
of information available on these chips.They are also easier
to learn than some others.
When I was learning to us uc's I got an intel databook
(EMBEDDED MICROCONTROLLERS AND PROCESSORS)
and read the 8051 chapters over and over and over. Phillips and
Siemens have the same books ,Phillips used to give them away
free they may still do that.