
Functional Description and Application Information
Resets
MM912F634
Freescale Semiconductor
71
4.6.2.18
Voltage Regulator Over-voltage Interrupt (VROVI)
Acknowledge the interrupt by reading the Voltage Status Register - VSR. To issue a new interrupt, the condition has to vanish
4.7
Resets
To protect the system during critical events, the MM912F634 analog die will drive the RESET_A pin low during the presence of
the reset condition. In addition, the RESET_A pin is monitored for external reset events. To match the MCU, the RESET_A pin
is based on the VDDX voltage level.
After an internal reset condition has gone, the RESET_A will stay low for an additional time tRST before being released. Entering
reset mode will cause all MM912F634 analog die registers to be initialized to their RESET default. The only registers with valid
information are the Reset Status Register (RSR) and the Wake-up Source Register (WUS).
4.7.1
Reset Sources
In the MM912F634 six reset sources exist.
4.7.1.1
POR - Analog Die Power On Reset
To indicate the device power supply (VS1) was below VPOR or the MM912F634 analog die was powered up, the POR condition
4.7.1.2
LVR - Low Voltage Reset - VDD
With the VDD voltage regulator output voltage falling below VLVR, the Low Voltage Reset condition becomes present. As the VDD
Regulator is shutdown once a LVRX condition is detected, The actual cause could be also a low voltage condition at the VDDX
4.7.1.3
LVRX - Low Voltage Reset - VDDX
With the VDDX voltage regulator output voltage falling below VLVRX, the Low Voltage Reset condition becomes present. See
4.7.1.4
WUR - Wake-up Reset
While in Sleep mode, any active wake-up event will cause a MM912F634 analog die transition from Sleep to Reset Mode. To
4.7.1.5
EXR - External Reset
Any low level voltage at the RESET_A pin with a duration > tRSTDF will issue an External Reset event. This reset source is also
active in Stop mode.
4.7.1.6
WDR - Watchdog Reset
Any incorrect serving if the MM912F634 analog die Watchdog will result in a Watchdog Reset. Please refer to the
Section 4.9,