FUNCTIONAL DEVICE OPERATIONS
LOGIC COMMANDS AND REGISTERS
MOD2, MOD1 - Mode Control Bits
1 = POR Reset has occurred
0 = POR Reset has not occurred
These write-only bits select the operating mode and allow
clearing the watchdog in accordance with Table 10 Mode
Control Bits.
Wake-Up Control Register - WUCR
This register is used to control the digital wake-up inputs.
Writing the WUCR will return the Wake-Up Status Register
(WUSR).
Table 10. Mode Control Bits
MOD2
MOD1
Description
0
0
1
1
0
1
0
1
Normal Mode
Stop Mode
Table 12. Wake-Up Control Register - $2
Sleep Mode
C3
C2
C1
C0
Normal Mode + Watchdog Clear
Write
L4WE
L3WE
L2WE
L1WE
Voltage Status Register - VSR
Reset
Value
1
1
1
1
Returns the status of the several voltage monitors. This
register is also returned when writing to the Mode Control
Register (MCR).
Reset
Condition
POR, Reset Mode or ext_reset
Table 11. Voltage Status Register - $0/$1
LxWE - Wake-up Input x Enable
S3
S2
S1
S0
This write-only bit enables/disables which Lx inputs are
enabled. In Stop and Sleep Mode the LxWE bit determines
which wake inputs are active for wake-up. If one of the Lx
inputs is selected on the analog multiplexer, the
corresponding LxWE is masked to 0.
Read
VSOV
VSUV
VDDOT
BATFAIL
VSOV - VSUP Over-Voltage
This read-only bit indicates an over-voltage condition on
the VS1 pin.
1 = Wake-Up Input x enabled.
0 = Wake-Up Input x disabled.
1 = Over-voltage condition.
0 = Normal condition.
Wake-Up Status Register - WUSR
This register is used to monitor the digital wake-up inputs
and is also returned when writing to the WUCR.
VSUV - VSUP Under-Voltage
This read-only bit indicates an under-voltage condition on
the VS1 pin.
Table 13. Wake-Up Status Register - $2/$3
1 = Under-voltage condition.
0 = Normal condition.
S3
S2
S1
S0
Read
L4
L3
L2
L1
VDDOT - Main Voltage Regulator Over-temperature
Warning
Lx - Wake-up input x
This read-only bit indicates that the main voltage regulator
temperature reached the Over-temperature Prewarning
Threshold.
This read-only bit indicates the status of the corresponding
Lx input. If the Lx input is not enabled, then the according
Wake-Up status will return 0.
1 = Over-temperature Prewarning
0 = Normal
After a wake-up from Stop or Sleep Mode these bits also
allow to determine which input has caused the wake-up, by
first reading the Interrupt Status Register (ISR) and then
reading the WUSR.
BATFAIL - Battery Fail Flag.
This read-only bit is set during power-up and indicates that
the 33912 had a Power-On-Reset (POR).
1 = Lx Wake-up.
0 = Lx Wake-up disabled or selected as analog input.
Any access to the MCR or VSR will clear the BATFAIL flag.
33912
Analog Integrated Circuit Device Data
Freescale Semiconductor
37
FREESCALE [ Freescale ]
