SCA8X0/21X0/3100 Series

VTI Technologies Oy

11/35

www.vti.fi

Doc. Nr. 82 694 00 C

Item

Procedure

Functions

Check

AVE forward

to check SPI

failure bits)

•

SPI ST=0

•

SPI SAT=0

•

dPAR, data

parity

5

Send calculated AVE forward

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-

6

Jump back to item 2

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-

For detailed SPI failure bit information see chapter 4.2 Error Conditioning

2.7

Recommended procedures or optional features

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.

2.7.1

SCA8x0/SCA21x0/SCA31x0

2.7.1.1

Read back procedure

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.

2.7.1.2

Checksum during operation

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.

2.7.1.3

Saturated data

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.

2.7.1.4

Noiseless output

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.

2.7.1.5

Component ID

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.

2.7.2

SCA8x0

2.7.2.1

Mass deflection during operation

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