SCA21X0 VTI [VTI technologies], SCA21X0 Datasheet - Page 14

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

3.1.4
3.1.4.1
s = sign bit
x = not used/defined bit
*) = positive/negative full-scale or saturation limit of ±2 g product is 2.27 g.
VTI Technologies Oy
www.vti.fi
+/-2g product
Bit number
SCA8x0
+1g position
-1g position
+Full-scale
-Full-scale
+/-2g product
Bit number
SCA31x0/SCA21x0
+1g position
-1g position
+Full-scale *)
-Full-scale *)
Acceleration MSB-register: Address 5'hex / 7'hex / 9'hex
Acc
Acc
Acc
DO7
b15
[ ]
[ ]
[ ]
mg
mg
mg
Output data conversion
=
=
=
DO6
b14
2g products
10
10
10
18
9
9
[
⎡
⎢
⎢
⎣
⎡
⎢
⎢
⎣
−
DOUT MSB bits(7:0)
DOUT MSB bits(7:0)
−
+
−
+
15
15
In SCA8X0 acceleration bits can be converted to mg acceleration (Acc) using following equation
and in SCA21X0/SCA31X0
where bits are defined according to following table.
In data output registers of SCA21X0/SCA31X0 there is reserved room for different g-ranges. To
make sure that same software works with different product types it is recommended to use
bits(15:2) for data conversion. If dynamic output range of product does not require bits b14 or b13
they include copy of sign bit b15.
If self-test (checksum, STC, STS) alarms it sets ST bit in SPI frame and forces output data to value
7FFF'hex (checksum fail) or to value FFFF'hex (STC/STS alarm).
In SCA21X0/SCA31X0 there is also possible to use 1-extra lsb bit (b1) for calculation to improve
resolution. In that case acceleration bits can be converted to mg acceleration (Acc) using following
equation
s
0
1
0
1
0
1
0
1
s
s
b
DO5
b
s
s
b13
⋅
9
8
⋅
⋅
2
2
2
1137.8
4551.1
11
⋅
⋅
13
14
2
2
14
14
0
1
1
0
0
1
0
1
+
7
7
+
+
b
+
+
14
b
b
DO4
b12
b
b
14
14
8
7
2275.6
568.9
⋅
⋅
2
⋅
13
13
⋅
⋅
1
1
0
0
0
0
1
1
2
2
10
2
2
6
6
12
13
+
+
+
+
DO3
+
b11
b
b
b
1137.8
13
284.4
b
b
7
6
12
12
13
13
1
0
1
0
0
1
1
0
⋅
⋅
⋅
2
2
2
⋅
⋅
5
5
9
2
2
+
+
11
12
+
DO2
b10
142.2
568.9
b
b
11
11
b
+
+
1
0
1
0
1
0
1
0
6
5
12
b
b
⋅
⋅
12
12
2
2
⋅
2
4
4
284.4
⋅
71.1
8
DO1
⋅
+
+
10
10
2
b9
2
0
1
1
0
1
0
1
0
+
10
b
b
11
b
5
4
11
+
+
⋅
⋅
2
b
b
2
Doc. Nr. 82 694 00 C
142.2
35.6
⋅
11
3
11
3
9
0
1
1
0
9
1
0
1
0
2
DO0
+
+
b8
7
⋅
⋅
b
+
b
2
2
4
3
10
9
b
17.8
71.1
⋅
10
⋅
8
0
1
1
0
8
0
1
1
0
+
+
2
2
Acceleration LSB-register: Address 4'hex / 6'hex / 8'hex
b
2
2
DO7
b
⋅
10
DOUT LSB bits(7:0)
DOUT LSB bits(7:0)
b7
+
10
+
2
35.56
8.89
6
b
b
7
0
1
1
0
7
0
1
1
0
⋅
+
⋅
2
3
2
2
8
b
⋅
⋅
9
2
2
9
+
17.78
DO6
4.44
⋅
+
+
b6
1
1
0
1
6
1
0
6
1
0
2
b
b
b
5
9
1
2
+
⋅
⎤
⎥
⎥
⎦
2
b
2.22
8.89
,
8
8
5
0
0
1
0
5
0
1
1
0
DO5
⎤
⎥
⎥
⎦
⋅
b5
2
.
4
1.11
4.44
+
4
0
0
1
0
4
1
1
1
0
b
7
DO4
b4
⋅
2.22
2
3
x
x
x
x
x
3
0
0
1
0
3
+
b
1.11
DO3
6
2
x
x
x
x
x
2
0
0
1
0
b3
⋅
2
2
1
x
x
x
x
x
1
x
x
x
x
x
+
SCA8X0/21X0/3100 Series
b
DO2
5
b2
⋅
0
x
x
x
x
x
0
x
x
x
x
x
2
+
-1000
-2275
-1000
-2275
1000
2274
1000
2274
b
[mg]
[mg]
[-]
[-]
4
DO1
b1
]
Bits (15:4) Bits (15:4)
Bits (15:2) Bits (15:2)
-2048
-2048
[Dec]
2047
[Dec]
2047
-900
-900
12b
900
900
DO0
b0
14/35
3C7C
[Hex]
[Hex]
3800
C7C
12b
384
7FF
800
384
7FF