mc33812 Freescale Semiconductor, Inc, mc33812 Datasheet - Page 13

• Manufacturer Part Number: mc33812
• Description: Multifunctional Ignition And Injector Driver
• Manufacturer: Freescale Semiconductor, Inc

are normally low and will go high when a fault is detected.
Toggling the respective input pin will clear the respective fault
pin if the fault has been cleared.
K-LINE COMMUNICATION (MTX, MRX, ISO9141)
communication link for the MCU to provide diagnostic support
for the system. MRX is the +5.0 V logic level serial output line
to the MCU. MTX is the +5.0 V logic level serial input to the
IC from the MCU. The ISO9141 pin is a bidirectional line,
consistent with the ISO9141 specification for signalling to and
from the MCU.
RESET (
the circuit, RESET is held low by an internal pull-down
resistor. When power is applied to the circuit and the voltage
on the VCC
(5.0 volts - 2% = 4.9 V) the RESET pin will remain at a low
level (open drain FET turned on) for a period of time equal to
the value WD
then go high and stay high until a watchdog RESET is
generated, or an under-voltage event on VCC occurs. The
Analog Integrated Circuit Device Data
Freescale Semiconductor
These three pins are used to provide an ISO914, K-line
The RESET pin is an open drain output.Without power on
RESET
SENSE
RESET
)
pin reaches the lower voltage threshold,
. After this time period, the RESET pin will
watchdog time and refresh features are controlled via the
WDRFSH line.
RELOAD AND REFRESH TIME (WDRFSH)
output to set up the initial reload time, WD
refresh the watchdog timer. See the description of the
watchdog timer for information on how to use this pin.
WATCHDOG INHIBIT(WD_INH)
ground. If desired, during software development, it can be
lifted from the ground pad and pulled high through an external
pull-up resistor. When high, WD_INH will prevent the
watchdog timer from causing a RESET because of a
watchdog timeout. The WD_INH should not be connected to
an MCU I/O pin or left floating in normal operation.
TEST PINS (TEST1, TEST2, AND TEST3)
engineering during the production testing of the 33812. They
are not to be used for any application purpose and must be
handled as specified in the pinout section of this document.
The WDRFSH pin is an input that is supplied by an MCU
The WD_INH, watchdog inhibit pin, is normally tied to
These three pins are used only by Freescale test
FUNCTIONAL PIN DESCRIPTION
FUNCTIONAL DESCRIPTION
RELOAD
, and to
33812
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