s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 112

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Low-Voltage Inhibit (LVI) Module
Once an LVI reset occurs, the MCU remains in reset until V
be above LVI
Operation). The output of the comparator controls the state of the LVIOUT flag in the LVI status register
(LVISR).
An LVI reset also drives the RST pin low to provide low-voltage protection to external peripheral devices.
11.3.1 Polled LVI Operation
In applications that can operate at V
polling the LVIOUT bit. In the configuration register, the LVIPWRD bit must be at 0 to enable the LVI
module, and the LVIRSTD bit must be at 1 to disable LVI resets.
11.3.2 Forced Reset Operation
In applications that require V
module to reset the MCU when V
and LVIRSTD bits must be at 0 to enable the LVI module and to enable LVI resets.
11.3.3 False Reset Protection
False reset protection is provided by the hysteresis in the LVI trip circuit (refer to
to
11.3.4 LVI Status Register
The LVI status register flags V
LVIOUT — LVI Output Bit
112
20.5 DC Electrical Characteristics
This read-only flag becomes set when the V
Table
11-1.) Reset clears the LVIOUT bit.
TRIPR
Address:
Reset:
Read:
Write:
for only one CPU cycle to bring the MCU out of reset (see
LVIOUT
$FE0C
At Level:
Bit 7
0
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
DD
DD
Figure 11-2. LVI Status Register (LVISR)
= Unimplemented
LVI
to remain above the LVI
DD
TRIPF
voltages below the LVI
6
0
0
Table 11-1. LVIOUT Bit Indication
V
V
falls to the LVI
DD
DD
DD
for hysteresis value (VHYS) and rising and falling LVI trip values.
< V
> LVI
< LVI
levels below the LVI
V
DD
DD
5
0
0
TRIPR
TRIPF
< LVI
DD
TRIPR
TRIPF
voltage falls below the LVI
4
0
0
level. In the configuration register, the LVIPWRD
TRIPF
TRIPF
DD
TRIPF
3
0
0
rises above a voltage, LVI
level, enabling LVI resets allows the LVI
level
Previous Value
level, software can monitor V
.
LVIOUT
2
0
0
0
1
TRIPF
11.3.2 Forced Reset
Table
1
0
0
voltage. (See
Freescale Semiconductor
11-1). Please refer
Bit 0
TRIPR
0
0
. V
DD
DD
by
must