User manual

...the world's most energy friendly microcontrollers
2012-04-24 - Giant Gecko Family - d0053_Rev0.96 98
www.energymicro.com
9 RMU - Reset Management Unit
0
1 2 3 4
SYSRESETREQ
WATCHDOG
BROWNOUT
POWERON
Reset Managem ent Unit
RESET
LOCKUP
RESETn
Quick Facts
What?
The RMU ensures correct reset operation.
It is responsible for connecting the different
reset sources to the reset lines of the
EFM32GG.
Why?
A correct reset sequence is needed to
ensure safe and synchronous startup of the
EFM32GG. In the case of error situations
such as power supply glitches or software
crash, the RMU provides proper reset and
startup of the EFM32GG.
How?
The Power-on Reset and Brown-out Detector
of the EFM32GG provides power line
monitoring with exceptionally low power
consumption. The cause of the reset may be
read from a register, thus providing software
with information about the cause of the reset.
9.1 Introduction
The RMU is responsible for handling the reset functionality of the EFM32GG.
9.2 Features
• Reset sources
• Power-on Reset (POR)
• Brown-out Detection (BOD) on the following power domains:
• Regulated domain
• Unregulated domain
• Analog Power Domain 0 (AVDD0)
• Analog Power Domain 1 (AVDD1)
• RESETn pin reset
• Watchdog reset
• EM4 wakeup reset from pin
• EM4 wakeup reset from Backup RTC interrupt
• Wakeup from Backup Mode
• Software triggered reset (SYSRESETREQ)
• Core LOCKUP condition
• EM4 Detection
• A software readable register indicates the cause of the last reset
9.3 Functional Description
The RMU monitors each of the reset sources of the EFM32GG. If one or more reset sources go active,
the RMU applies reset to the EFM32GG. When the reset sources go inactive the EFM32GG starts