In Active mode, the type of the main
voltage regulator supplying VDDCORE can be switched on the fly. The two alternatives are a
LDO regulator and a Buck converter.
The main voltage regulator switching sequences are
as follows:
- The user changes the value of the
Voltage Regulator Selection bit in the Voltage Regulator System Control register
(VREG.SEL)
- The start of the switching sequence
is indicated by clearing the Voltage Regulator Ready bit in the STATUS register
(STATUS.VREGRDY=0)
- Once the switching sequence is
completed, STATUS.VREGRDY will read '1'
The Voltage Regulator Ready (VREGRDY) interrupt can also be used to detect a
zero-to-one transition of the STATUS.VREGRDY bit.