FUNCTIONAL DEVICE OPERATIONS
OPERATIONAL MODES
Table 5. Operating Modes Overview
Normal
Mode
Function
Reset Mode Normal Request Mode
Stop Mode
Sleep Mode
VDD
HVDD
Full
Full
SPI(55)
Full
SPI
Stop
-
-
-
-
LSx
-
SPI/PWM(56)
SPI/PWM(56)
SPI
SPI/PWM
SPI/PWM
SPI
-
-
HSx
-
-
Note(57)
Note(58)
Analog Mux
Lx
-
-
-
Inputs
Inputs
On
Wake-up
-
Wake-up
-
Current Sense
LIN
On
-
On
Rx-Only
150ms (typ.) timeout
On
Full/Rx-Only Rx-Only/Wake-up Wake-up
Watchdog
VSENSE
Notes
-
On(59)/Off
On
-
-
-
On
VDD
55. Operation can be enabled/controlled by the SPI.
56. Operation can be controlled by the PWMIN input.
57. HSx switches can be configured for cyclic sense operation in Stop Mode.
58. HSx switches can be configured for cyclic sense operation in Sleep Mode.
59. Windowing operation when enabled by an external resistor.
High-voltage Interrupt:
INTERRUPTS
Interrupts are used to signal a microcontroller that a
peripheral needs to be serviced. The interrupts which can be
generated, change according to the operating mode. While in
Normal and Normal Request Modes, the 33912 signals
through interrupts special conditions which may require a
MCU software action. Interrupts are not generated until all
pending wake-up sources are read in the Interrupt Source
Register (ISR).
Signals when the supply line (VS1) voltage increases
above the VSOV threshold (VSOV).
Over-temperature Prewarning:
Signals when the 33912 temperature has reached the pre-
shutdown warning threshold. It is used to warn the MCU that
an over-temperature shutdown in the main 5V regulator is
imminent.
While in Stop Mode, interrupts are used to signal wake-up
events. Sleep Mode does not use interrupts. Wake-up is
performed by powering-up the MCU. In Normal and Normal
Request Mode the wake-up source can be read by SPI.
LIN Over-current Shutdown / Over-temperature
Shutdown / TXD Stuck At Dominant / RXD Short-circuit:
These signal fault conditions within the LIN interface will
cause the LIN driver to be disabled, except for the LIN over-
current condition. In order to restart operation, the fault must
be removed and must be acknowledged by reading the SPI.
The interrupts are signaled to the MCU by a low logic level
of the IRQ pin, which will remain low until the interrupt is
acknowledged by a SPI read. The IRQ pin will then be driven
high.
The LINOC bit functionality in the LIN Status Register
(LINSR) is to indicate an LIN over-current has occurred and
the driver remains enabled.
Interrupts are only asserted while in Normal, Normal
Request and Stop Mode. Interrupts are not generated while
the RST pin is low.
The following is a list of the interrupt sources in Normal and
Normal Request Modes. Some of these can be masked by
writing to the SPI - Interrupt Mask Register (IMR).
High Side Over-temperature Shutdown:
Signals a shutdown in the high side outputs.
Low Side Over-temperature Shutdown:
Low-voltage Interrupt:
Signals a shutdown in the low side outputs.
Signals when the supply line (VS1) voltage drops below
the VSUV threshold (VSUV).
RESET
To reset a MCU the 33912 drives the RST pin low for the
time the reset condition lasts.
33912
Analog Integrated Circuit Device Data
Freescale Semiconductor
27
FREESCALE [ Freescale ]
