Low-Voltage Inhibit (LVI)
Technical Data
MC68HC908GP32
•
MC68HC08GP32
—
Rev. 6
192
Low-Voltage Inhibit (LVI)
MOTOROLA
14.4.2 Forced Reset Operation
In applications that require V
DD
to remain above the V
TRIPF
level,
enabling LVI resets allows the LVI module to reset the MCU when V
DD
falls below the V
TRIPF
level. In the configuration register, the LVIPWRD
and LVIRSTD bits must be at logic 0 to enable the LVI module and to
enable LVI resets.
14.4.3 Voltage Hysteresis Protection
Once the LVI has triggered (by having V
DD
fall below V
TRIPF
), the LVI
will maintain a reset condition until V
DD
rises above the rising trip point
voltage, V
TRIPR
. This prevents a condition in which the MCU is
continually entering and exiting reset if V
DD
is approximately equal to
V
TRIPF
. V
TRIPR
is greater than V
TRIPF
by the hysteresis voltage, V
HYS
.
14.4.4 LVI Trip Selection
The LVI5OR3 bit in the configuration register selects whether the LVI is
configured for 5-V or 3-V protection.
NOTE:
The microcontroller is guaranteed to operate at a minimum supply
voltage. The trip point (V
TRIPF
[5 V] or V
TRIPF
[3 V]) may be lower than
this. (See
Section 23. Electrical Specifications
for the actual trip point
voltages.)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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