4 Hardware
UM0178
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the current limit condition was removed, this fault condition does not interfere with the operation
of any of the other output channels.
Channels 3 and 4 of the L9658 can by used to provide an analog feed back current as a 1/
100th ratio of the sense current in this mode internal FIFO and decoder are bypassed. This will
allow the IF3/V3 and IF4/V4 pins to be connected to a resistor to ground and provide an analog
voltage equivalent to the sense current to be read by an A/D port. Otherwise the IF3/V3 and
IF4/V4 pins can be configured as discrete output pins that provide logic level output voltage of
the sensed current based on the internal current threshold set by the user through the CCR
Register, which when used in conjunction with satellite sensors connected to channels 3 and 4
it can provide raw data out of the satellite message bypassing the internal decoder.
4.5.3 Satellite
SPI
interface
The board support up to 6 satellites (4 handled from L9658 and 2 from L9654).
The L9658/L9654 support two different communication protocols that are widely used by
different automotive manufactures. One is based on the protocol used by Delphi satellite
sensors and the other is a generic protocol that supports variable length messages based on
BOSH, PAS3 and PAS4 protocols.
All decoded satellite messages are communicated to the external microcontroller via SPI. The
MOSI input takes data from the master microprocessor while either CS_S1 (chip select of the
L9658) or CS_S2 (chip select of the L9654) is asserted.The MISO reported the status of L9658/
L9654 output channels. It is possible drive the two satellite interfaces (L9658/L9654) separately
because there are two chip select, CS_S1 and CS_S2.
4.5.4
Board satellite functionality
Satellites can be connected directly to the ASIC’s through pin 1 of jumpers J5-J8 and J54-J55.
Table 1.
Satellite connector
Diagnostic functionality of satellite communication can be tested using jumper J14. Opening
this jumper interrupts the SCLK signal of the SPI used for satellite and deployment thus
blocking any communication between the micro and the ASIC.
It is possible to simulate satellite signals by closing jumpers J5-J8 and J54-J55 and providing
the appropriate signal to pins DICH1-DICH6 on the CPU board connector. You must drive the
base of the BJT with a particular signal in order to generate the correct word to decode with
manchester decoding and then to transmit via SPI. This dynamic digital signal shall be
generated by using 2 PWM outputs provide on ST30F7xx board (or an ST10F27x board). This
signal will be sent into the base of the BJT’s to simulate the local acceleration values.
Name
Figure
Description
J5 pin 1
Figure 4
L9658 satellite channel 1 (ICH1)
J6 pin 1
Figure 4
L9658 satellite channel 2 (ICH2)
J7 pin 1
Figure 4
L9658 satellite/sensor channel 3 (ICH3)
J8 pin 1
Figure 4
L9658 satellite/sensor channel 4 (ICH4)
J54 pin 1
Figure 4
L9654 satellite channel 1 (ICH1)
J55 pin 1
Figure 4
L9654 satellite channel 2 (ICH2)
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