± 2g / 4g / 8g / 16g Tri-axis Digital
Accelerometer Technical
Reference Manual
PART NUMBER:
KX132-1211
Rev. 1.0
31-Jul-2019
36 Thornwood Dr.
–
Ithaca, NY 14850
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–
All Rights Reserved
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Page
41
of
73
1.22 SELF_TEST (0X5D)
Self-Test Enable register.
W
W
W
W
W
W
W
W
0
0
0
0
0
0
0
0
Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
00000000
Address:
0x5D
To perform the self-test, the following procedure is required:
1. Set STPOL bit to 1 in INC1 register to set the polarity of the self-test mode to positive.
2. Set PC1 bit to 1 in CNTL1 register to enable KX132-1211.
3. Write 0xCA to this register to enable the MEMS self-test function.
Once the self-test function is enabled, electrostatic-actuation of the accelerometer, results in a DC shift of the X, Y and
Z axis outputs. Calculate the self-test (ST) response using Equation 2:
𝑆𝑇[𝑔] =
(𝑂𝑈𝑇𝑃𝑈𝑇
𝑆𝑇_𝑂𝑁
[𝑐𝑜𝑢𝑛𝑡𝑠]) − (𝑂𝑈𝑇𝑃𝑈𝑇
𝑆𝑇_𝑂𝐹𝐹
[𝑐𝑜𝑢𝑛𝑡𝑠])
𝑆𝑒𝑛𝑠𝑖𝑡𝑖𝑣𝑖𝑡𝑦 [
𝑐𝑜𝑢𝑛𝑡𝑠
𝑔
]
Equation 2:
Self-Test (ST) Response Calculation
The self test response should be compared to the product specifications to determine if the MEMS response is within
the specified range (consult Mechanical Specification table of KX132-1211 product specifications).
To disable the self-test mode any of the following methods can be used:
▪
Power cycle KX132-1211
Or
▪
Perform software reset by setting SRST bit to 1 in CNTL 2 register
Or
1. Set PC1 bit to 0 in CNTL1 register to set KX132-1211 in Standby mode.
2. Write 0x00 to this register to disable the self-test mode.
Note, this is a write-only register. Read back value from this register will always be 0x00.
