mc33789 Freescale Semiconductor, Inc, mc33789 Datasheet - Page 34

• Manufacturer Part Number: mc33789
• Description: Airbag System Basis Chip Sbc With Power Supply And Psi5 Sensor Interface
• Manufacturer: Freescale Semiconductor, Inc

FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
SERIAL PERIPHERIAL INTERFACE (SPI)
features:
LIN Physical Layer
three communication speeds by changing the output slew
rate:
configured to directly output one of four satellite sensor
channel's Manchester code.
34
33789
• 16-bit data frame
• Up to 8.0 MHz SPI clock
The LIN physical layer is LIN 2.1 compliant, and supports
• LIN: up to 10.4 kBaud
• LIN: up to 20 kBaud
• ISO 9141 (K-line): up to 100 kBaud
This external communication interface can also be
The 33789 SPI interface uses a slave configuration. It
GND_LIN
SCRAP
RXD
TXD
LIN
Figure 22. Communication Interfaces Block Diagram
Interface
LIN
Figure 21. V
AOUT
Safing
vs. I
INx
I
INx
Monotonic Operation
SAFING LOGIC
is independent of the MCU, to monitor both on-board sensors
and satellite sensors, to determine the vehicle safety status,
and verify the necessity to warrant Arming deployment of the
airbag system. The functions of each section can be
summarized as following:
(mA)
1. SPI Monitor and Decoder:
• 5.0 or 3.3 V compatibility (receives 3.3 V SPI inputs
• Three extra chip selects CS_A, CS_B, and CS_C to
Interface
• Extracts all of the sensor data transferred on the SPI in
without a level shifter)
support SPI monitor extract on-board digital sensor
data for up to four sensors.
SPI
responding the MCU requests
Monitor
The Safing Logic block utilizes a logic structure, which
SPI
Analog Integrated Circuit Device Data
SI
SO
SCK
CS
CS_A
CS_B
CS_C
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