CPU_42A-V1
CPU Board XMC4200 Actuator
Hardware Description
Board User's Manual
21
Revision 1.0, 2013-02-19
2.9
RTC
The XMC4200 CPU has two power domains, the Core Domain and the Hibernate Domain.
The Core Domain (VDDP pins) is connected to the VDD3.3 rail. An on-board LDO voltage regulator generates
VDD3.3 (3.3 V) out of VDD5 (5 V).
The Hibernate Domain is powered via the auxiliary supply pin VBAT, which is supplied by either a 3 V coin cell
(size 1216, 1220 or 1225) plugged into the battery holder or 3.3 V (VDD3.3) generated by the on-board voltage
regulator.
Figure 18 Battery Holder for Coin Cells
The Real Time Clock (RTC) is located in the hibernate domain. Even if the Core Domain is not powered the
Hibernate Domain will operate if VBAT is supplied. The RTC keeps running as long as the Hibernate Domain is
powered via the auxiliary supply VBAT.
Figure 19 XMC4200 Power Domains and Real Time Clock
Battery.emf
Battery
Holder
Core Domain
CPU
Internal OSC
Hibernate Domain
VBAT
32.768 kHz
XMC4200
VDDP
IFX1763
LDO
Voltage Reg.
VDD3.3
+
RTC
SPI
RTC.emf
Battery
12 MHz
External OSC
