MM908E624ACEW/R2 FREESCALE [Freescale Semiconductor, Inc], MM908E624ACEW/R2 Datasheet - Page 27

• Manufacturer Part Number: MM908E624ACEW/R2
• Description: Integrated Triple High Side Switch with Embedded MCU and LIN Serial Communicationfor Relay Drivers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

WINDOW WATCHDOG
resistor at the WDCONF terminal. The watchdog is cleared
through by the MODE1:2 bits in the SPI Control register (refer
to
watchdog is cleared in the closed window or has not been
cleared at the end of the open window, the watchdog will
generate a reset on the
device.
(150 ms) (first watchdog clear) has no window.
Watchdog Configuration
period is selected (typ. 150 ms). If no watchdog function is
required, the WDCONF terminal must be connected to GND.
formula:
VOLTAGE REGULATOR
voltage regulator to provide internal power and external
power for the MCU. The on-chip regulator consist of two
elements, the main voltage regulator and the low-voltage
reset circuit.
and provides a regulated V
the device. The output of the regulator is also connected to
the VDD terminal to provide the 5.0 V to the microcontroller.
Current Limit (Over-current) Protection
against over-current and short circuit conditions.
Analog Integrated Circuit Device Data
Freescale Semiconductor
Table
The window watchdog is configurable using an external
A watchdog clear is only allowed in the open window. If the
Note The watchdog clear in Normal request mode
If the WDCONF terminal is left open, the default watchdog
The watchdog period is calculated using the following
The 908E624 chip contains a low-power, low dropout
The V
The voltage regulator has current limit to protect the device
no watchdog clear allowed
WD timing selected by resistor on WDCONF terminal.
8, page 29).
DD
WD timing x 50%
Figure 16. Window Watchdog Operation
Window closed
t
PWD
regulator accepts an unregulated input supply
[ms] = 0.991
WD period (P
RST_A
DD
*
supply to all digital sections of
terminal and reset the whole
R
(t
EXT
PWD
WD
)
for watchdog clear
WD timing x 50%
[k Ω ] + 0.648
)
Window open
Over-temperature Protection
protection having an over-temperature warning (Interrupt -
VDDT) and an over-temperature shutdown.
Stop Mode
regulated output voltage. The Stop mode regulator has a
limited output current capability.
Sleep Mode
off.
FACTORY TRIMMING AND CALIBRATION
parameters (e.g., ICG trim value) are stored in the flash
memory of the device. The following flash memory locations
are reserved for this purpose and might have a value different
from the “empty” (0xFF) state:
has to take care not to erase or override these values. If these
parameters are not used, these flash locations can be erased
and otherwise used.
Trim Values
is explained in the following.
Internal Clock Generator (ICG) Trim Value
create a stable clock source for the microcontroller without
using any external components. The untrimmed frequency of
the low-frequency base clock (IBASE), will vary as much as
±25 percent due to process, temperature, and voltage
dependencies. To compensate for these dependencies, an
ICG trim value is located at address $FDC2. After trimming
the ICG, a range of typ. ±2% (±3% max.) at nominal
conditions (filtered (100nF) and stabilized (4,7uF) V
T
(VDD) as indicated in the 68HC908EY16 data sheet.
Trim Register ICGTR at address $38 of the MCU.
OPERATING MODES OF THE MCU
the MCU, refer to the MC68HC908EY16 data sheet.
Ambient
The voltage regulator also features an over-temperature
During Stop mode, the Stop mode regulator supplies a
In Sleep mode the voltage regulator external V
To enhance the ease-of-use of the 908E624, various
• 0xFD80 :0xFDDF Trim and Calibration Values
• 0xFFFE : 0xFFFF Reset Vector
In the event the application uses these parameters, one
The usage of the trim values, located in the flash memory,
The internal clock generator (ICG) module is used to
To trim the ICG, these values have to be copied to the ICG
Important The value has to be copied after every reset.
For a detailed description of the operating modes of
~23°C) and will vary over-temperature and voltage
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
DD
DD
is turned
908E624
= 5V,
27