Arming Spi Interface; Table 3. Arming Interface Jumpers; Figure 5. Spi Configuration On Arming For Eva Board - STMicroelectronics MB467 User Manual

4 Hardware
There are on board two different deployment enables for L9658 and L9654. When these pins
are asserted, L9658/L9654 are able to turn on its high (SQH) and low side (SQL) drivers upon
receiving a valid deployment command or a MOS diagnostic request. When a deployment is
initiated, it cant be terminated, except during a reset event.
4.6.1

Arming SPI interface

L9654 and L9658 arming commands are based on 8bit SPI messages.
In a real airbag system, all the devices should be daisy-chained. Here, as this board has been
designed for training purposes for each ASIC, ASIC's are connected on the same SPI and
selected with different chip selects CS_A1 and CS_A2. You find the chips select on the CPU
board connector at the position D30 and C27.
Figure 5.
The above figure is representing the SPI configuration for the system evaluation board where
ASIC's are sharing a common SPI.
Diagnostic functionality of the arming interface can be tested using jumper J20. Opening this
jumper interrupts the SCLK_A signal of the SPI used for arming thus blocking any
communication between the micro and the ASIC.
Table 3.
Name
J20
16/37
SPI configuration on Arming for eva board
CS_A2 CS_A1
µP
MOSI
MISO
SCLK
Arming interface jumpers
Figure
Figure 7
CS_A1
CS_A2
IC_1
IC_2
MOSI_A
MOSI_A
MISO_A
MISO_A
SCLK_A
SCLK_A
Description
Interrupt SPI communication for Arming
UM0178