A4910 Datasheet, PDF (26/36 Pages) Allegro MicroSystems – Automotive 3-Phase MOSFET Driver

A4910
Automotive 3-Phase MOSFET Driver
At power-up or after a power-on reset, the FF bit and the POR bit
are set and all other bits are reset. This indicates to the external
controller that a power-on reset has taken place and all registers
have been reset. Note that a power-on reset only occurs when the
VDD supply rises above its undervoltage threshold. Power-on
reset is not affected by the state of the VBB supply or VREG.
The first bit in the register is the Diagnostic register flag. This
is high if any bits in the Diagnostic register are set or if a serial
write error or parity error has occurred. When STRn goes low
to start a serial write SDO comes out of its high impedance state
and outputs the serial register fault flag irrespective of the register
address or state of the WR bits. This allows the main controller to
poll the A4910 through the serial interface to determine if a fault
has been detected. If no faults have been detected then the serial
transfer may be terminated without generating a serial read fault
by ensuring that SCK remains high while STRn is low. When
STRn goes high the transfer will be terminated and SDO will go
into its high impedance state.
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