CMA3000-D0X VTI Hamlin, CMA3000-D0X Datasheet - Page 15

• Manufacturer Part Number: CMA3000-D0X
• Description: Cma3000-d0x Series 3-axis Accelerometer
• Manufacturer: VTI Hamlin

VTI Technologies Oy
www.vti.fi
Address: 09h
Register name: MDTHR, Motion detection threshold value register
Table 5. Bit level description in [mg] for motion detection threshold of CMA3000-D01.
x=not used bit
Address: 0Ah
Register name: MDFFTMR, Motion and free fall detection time register
The LSB bit weighting for MDTMR and FFTMR bits are converted to seconds by using the currently
configured CMA3000 output data rate (ODR), as follows:
Were the ODR is the currently configured CMA3000 output data rate, which is defined by MODE
bits (bits [3:1] in CTRL register). An example for CMA3000-D01 timer bit weighting is presented in
Table 6 below.
Table 6. An example for CMA3000-D01 MDTMR and FFTMR bit level descriptions in [ms].
Register bit number
Timer bit number
CMA3000-D01,
MODE bits x10
ODR: 400Hz
CMA3000-D01,
MODE bits x01
ODR: 100Hz
CMA3000-D01,
MODE bits 100
ODR: 10Hz
x=not used bit
Range
Bits
Bits
8g
6:0
7:4
3:0
7
Timer
Mode
Mode
G_RANGE
RW
RW
RW
MDTMR
FFTMR
0
Value
Initial
Initial Value
8h
LSB
0
LSB
MDTMR
Doc.Nr. 8281000.12
[sec] = 1 / ODR[Hz]
3h
3h
[sec] = 1 / ODR[Hz], and
B7
b3
x
x
x
B7
MDTHR[6:0]
x
Name
MDTMR
400
B6
b2
x
x
4571
B6
MDTMR
MDTMR[3:0]
FFTMR [3:0]
Name
MDTMR
2286
200
Description
Reserved
Motion detection threshold level absolute value. See
detailed bit level weighting in Table 5 (bits [6:0])
B5
B5
B1
x
x
1142
1/10s =
100 ms
MDTMR
B4
B4
b0
x
x
Description
Motion detection timer bits
Free fall detection timer bits
571
B3
FFTMR
20
80
B3
b3
x
286
B2
FFTMR
40
10
B2
b2
x
143
FFTMR
B1
CMA3000-D0X Series
FFTMR
20
B1
B1
1/14 = 71 mg
5
x
B0
1/400s =
1/100s =
2,5 ms
10 ms
FFTMR
Rev. 0.12
B0
b0
x
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