L9822EPD013TR Datasheet, PDF (12/17 Pages) STMicroelectronics – Octal serial solenoid driver

Functional description
L9822E
4.6
Fault conditions check
Checking for fault conditions may be done in the following way. Clock in a new control byte.
Wait 160 µs or so to allow the outputs to settle.
Clock in the same control byte and observe the diagnostic data that comes out of the device.
The diagnostic bits should be identical to the bits that were first clocked in. Any differences
would point to a fault on that output. If the output was programmed ON by clocking in a zero,
and a one came back as the diagnostic bit for that output, the output pin was still high and a
short circuit or overload condition exists.
If the output was programmed OFF by clocking in a one, and a zero came back as the
diagnostic bit for that output, nothing had pulled the output pin high and it must be floating,
so an open circuit condition exists for that output.
Figure 4. Byte timing with asynchronous reset.
RESET
CE
SCLK
SI
SO
#7 #6 #5 #4 #3 #2 #1
#7 #6 #5 #4 #3 #2 #1 #0
OUTPUTS
OLD
Figure 5. Timing diagram.
CE
SCLK
SI
TLEAD
I/FOP TWSCKH
TEN
#7
#6
TWSCKL
TSU TH
DI7
TV
SO
D07
D06
OUTS
OLD
NEW
RESET
FAULTS
TLAG
#0
THD
DI0
TDIS
D00
FAULT-INDUCED
TPHL
TURN/OFF
TPLH
NEW
TUD
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