MCZ33975EK Freescale Semiconductor, MCZ33975EK Datasheet - Page 27

• Manufacturer Part Number: MCZ33975EK
• Description: IC DETECTOR MULT SWITCH 32-SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MCZ33975EK

• Applications: Automotive
• Interface: SPI
• Voltage - Supply: 5.5 V ~ 28 V
• Package / Case: 32-SOIC (7.5mm Width) Exposed Pad, 32-eSOIC, 32-HSOIC
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Therefore, when sending the sleep command, one device will
enter sleep before the other. For multiple devices in a system,
it is recommended that the devices are controlled in serial (S0
from first device is connected to SI of second device). With
two devices, 48 clock pulses are required to shift data in.
When the
both
power supply. The
interrupt pin on the MCU, or may have their own dedicated
interrupt to the MCU.
sending the sleep command. With the devices connected in
serial and the sleep command sent, both will enter Sleep
Mode on the rising edge of
the
WAKE
command (
With this event, the device that detects this input will not
transition to Sleep Mode, while the second device will enter
Sleep Mode. In this case, two switch status commands must
be sent to receive accurate switch status data. The first
switch status command will wake the device in Sleep Mode.
Switch status data may not be valid from the first switch
status command because of the time required for the input
voltage to rise above the 4.0V input comparator threshold.
This time is dependant on the impedance of SGn or SPn
node. The second switch status command will provide
accurate switch status information. It is recommended that
the software wait 10ms to 20ms between the two switch
status commands, allowing time for switch input voltages to
stabilize. With all switch states acknowledged by the MCU,
the sleep sequence may be initiated. All parameters for Sleep
Mode should be updated prior to sending the sleep
command.
Analog Integrated Circuit Device Data
Freescale Semiconductor
The transition from Normal to Sleep Mode is done by
A condition exists where the MCU is sending the sleep
WAKE
WAKE
pin will transition low, waking the other device.
WAKE
pin will be logic [1]. If either device wakes up, the
CS
pins should be connected to the enable pin on the
logic [0]) and a switch input changes state.
feature is used to enable the power supply,
INT
pins may be connected to one
CS
. When Sleep Mode is entered,
pin. A POR circuit monitors the internal 5.0V supply. In the
event of transients on the VPWR pin, an internal reset may
occur. Upon reset the 33975 will enter Normal Mode with the
internal registers as defined in
it is recommended that the MCU periodically update all
registers internal to the IC.
USING THE
designed to control an enable pin on system power supply.
While in the Normal Mode, the
the power supply. In the Sleep Mode, the
disabling the power supply. The
up to the internal 5.0V supply but may be pulled up through a
resistor to V
pulled up to the VDD supply through a resistor, as shown in
Figure
pin low, causing the 33975 to enter the Normal Mode. The
power supply will then be activated, supplying power to the
VDD pin and the microprocessor and the 33975. The
microprocessor can determine the source of the wake-up by
reading the interrupt flag.
COST AND FLEXIBILITY
interfaces have many discrete components. Discrete
components on standard PWB consume board space and
must be checked for solder joint integrity. An integrated
approach reduces solder joints, consumes less board space,
and offers wider operating voltage, analog interface
capability, and greater interfacing flexibility.
The 33975 IC has an internal 5.0V supply from the VPWR
The 33975 provides a
When the WAKE output is not used the pin should be
During the Sleep Mode, a switch closure will set the
Systems requiring a significant number of switch
16, page 28).
PWR
WAKE
supply (see
FEATURE
WAKE
Figure
Table
WAKE
WAKE
output and wake-up input
17, page 28).
TYPICAL APPLICATIONS
15, page 20. Therefore
OPERATIONAL MODES
output is low, enabling
pin has a passive pull-
WAKE
pin is high,
WAKE
33975
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