mma1605nwr2 Freescale Semiconductor, Inc, mma1605nwr2 Datasheet - Page 26

• Manufacturer Part Number: mma1605nwr2
• Description: Dsi Inertial Sensor
• Manufacturer: Freescale Semiconductor, Inc

26
3.5.3.3
3.5.3.4
signal processing chain is delayed one sample time. On reception of an acceleration data request, the transmitted data is inter-
polated from the 2 previous samples, resulting in a latency of one sample time, and a maximum signal jitter of ±1/16 of a sample
time. Reference
3.5.3.5
the device.
3.5.3.6
register. When the PCM function is enabled, a 4 MHz Pulse Code Modulated signal proportional to the upper 9 bits of the accel-
eration response is output onto the PCM pin. The PCM output is intended for test use only. A block diagram of the PCM output
is shown in
MMA16xxNW
The device includes internal compensation circuitry to compensate for sensor offset, sensitivity and non-linearity.
The device includes 16 to 1 linear data interpolation to minimize the system sample jitter. Each result produced by the digital
The 26 bit digital output from the DSP is clipped and scaled to a 10-bit or 8-Bit word which covers the acceleration range of
The device provides the option for a PCM output function. The PCM output is activated if the PCM bit is set in the DEVCFG2
Sample updated every 16μS
Output Scaling
D_x[9:1]
Figure 18
Figure
D25 D24 D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11 D10 D9
Compensation
Data Interpolation
Output Scaling
PCM Output Function
10 Bit Data Word
9 Bit Data Word
8 Bit Data Word
Figure 8
Over Range
19.
shows the method used to establish the acceleration data word from the 26-bit DSP output.
for more information regarding interpolation and data latency.
9
D21 D20 D19 D18 D17 D16 D15 D14 D13 D12
D21 D20 D19 D18 D17 D16 D15 D14 D13
D21 D20 D19 D18 D17 D16 D15 D14
Figure 19. PCM Output Function Block Diagram
A
B
9 Bit ADDER
Figure 18. Output Scaling Diagram
CARRY
f
CLK
SUM
Signal
= 4 MHz
9
9
D
D
CLK
D
CLK
D
CLK
D
CLK
D
CLK
D
CLK
D
FF
CLK
D
Noise
FF
CLK
FF
CLK
FF
Using Truncation
FF
FF
FF
Using Truncation
FF
FF
Q
Q
Using Truncation
Q
Q
Q
Q
Q
Q
Q
Q
D8
Q
Q
Q
Q
Q
Q
Q
Q
...
Margin
D2
Freescale Semiconductor
D1
D0
PCM
Sensors