SCA21X0 VTI [VTI technologies], SCA21X0 Datasheet - Page 11

• Manufacturer Part Number: SCA21X0
• Description: VTI Automotive Digital Accelerometer Platform
• Manufacturer: VTI [VTI technologies]

2.7 Recommended procedures or optional features
2.7.1
2.7.1.1
2.7.1.2
2.7.1.3
2.7.1.4
2.7.1.5
2.7.2
2.7.2.1
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SCA8x0
SCA8x0/SCA21x0/SCA31x0
Read back procedure
Checksum during operation
Saturated data
Noiseless output
Component ID
Mass deflection during operation
For detailed SPI failure bit information see chapter 4.2 Error Conditioning
Product family components have different features, which are not required during normal operation.
However, they are recommended in some cases if they are seen important from system
perspective.
It is recommended to read back every write command to compare read data to the write command.
This way it is detected very unlikely failures in MCU, in SPI wiring, in SPI interface, in system clock
or inside state machine.
Checksum is calculated for component register values that control the operation of product. Data is
read from non-volatile memory to these registers during start-up and checksum is calculated
automatically. It is possible to repeat checksum calculation during normal operation by CTRL
register command and test result can be seen from STATUS register (see more info in 3.2.1 and
3.1.6). In multi-axis products test result can be seen also from SPI frame. By repeating checksum
during normal operation, it is possible to detect very unlikely intermittent or static bit failures in
register map.
Output data saturates to predefined value if product dynamic range is exceeded. If output data has
been saturated it should be considered invalid and it should not be used for system controlling.
Output data saturation can also be indication of some very unlike component failure.
Valid acceleration output includes always some noise. If output data is constant, it can be indication
of system error and data is not valid anymore. Therefore it is useful to monitor noise or deviation of
output data.
Each product family component type has unique identification number, which is stored to non-
volatile memory (see 3.3.2). This number can be used for example in production line to check that
correct component is mounted to the system. In some cases it may be used for MCU software
controlling.
Mass deflection self-test is performed automatically to both direction in start-up. Mass deflection
can be performed during operation if requested by user. Test is started and direction is controlled
Item
5
6
Procedure
Send calculated AVE forward
Jump back to item 2
Doc. Nr. 82 694 00 C
Functions
AVE forward
to check SPI
failure bits)
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Check
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SPI ST=0
SPI SAT=0
dPAR, data
parity
SCA8X0/21X0/3100 Series
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