Hello,
Sure, let me explain.
VCORE is a synchronous buck converter with integrated FETs. VCORE is dedicated for microcontroller core supply. Output DC current up to 0.8 A or 1.65 A (depending on part number).

Output voltage range setting from 0.8 V to 3.35 V (OTP configuration, 10 mV step) which will be modified from the OTP configuration, please see OTP_CORE_VOLT1 register bit description.

So, if you want Core voltage to 1.2V use 28h.