Functional description of the SPI L9953 / L9953XP
28/38 Doc ID 14278 Rev 4
Table 20. SPI - input data and status registers 1
Bit
Input register 1 (write) Status register 1 (read)
Name Comment Name Comment
23 Enable bit
If Enable bit is set the device
will be switched in active mode.
If Enable Bit is cleared device
goes into standby mode and all
bits are cleared. After power-
on reset device starts in
standby mode.
Always 1
A broken VCC-or SPI-
connection of the L9953
can be detected by the
microcontroller, because
all 24 bits low or high is
not a valid frame.
22
OUT8 OC
Recovery
Enable
In case of an over-current
event the over-current status
bit (Status Register 0) is set
and the output is switched off.
If the over-current Recovery
Enable bit is set the output will
be automatically reactivated
after a delay time resulting in a
PWM modulated current with a
programmable duty cycle (Bit
21 of Input Data Register 0).
Depending on occurrence of
Overturned Event and internal
clock phase it is possible that
one recovery cycle is executed
even if this bit is set to zero.
VS overvoltage
In case of an overvoltage
or under voltage event
the corresponding bit is
set and the outputs are
deactivated. If Vs voltage
recovers to normal
operating conditions
outputs are reactivated
automatically.
21 0 / 1 VS undervoltage
20
OUT7 OC
Recovery
Enable
Thermal shutdown
In case of a thermal
shutdown all outputs are
switched off. The
microcontroller has to
clear the TSD bit by
setting the Reset Bit to
reactivate the outputs.
19
OUT6 OC
Recovery
Enable
Temperature
warning
The TW bit can be used
for thermal management
by the microcontroller to
avoid a thermal
shutdown. The
microcontroller has to
clear the TW bit.
18 0 / 1 Not ready bit
After switching the
device from standby
mode to active mode an
internal timer is started
to allow charge pump to
settle before the outputs
can be activated. This bit
is only present during
start up time
Since this bit is
controlled by internal
clock it can be used for
synchronizing testing
events(e.g. measuring
filter times).
