MMA685X datasheet(25/52 Pages) FREESCALE

Part #	MMA685X

Description	Single-Axis SPI Inertial Sensor

PDF	52 Pages

Scroll/Zoom	100%

Manufacturer	FREESCALE [Freescale Semiconductor, Inc]

Direct Link	http://www.freescale.com

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Freescale Semiconductor, Inc.

MMA685x

3.8.1

DSP Clock

The DSP is clocked at 8 MHz, with an effective 6MHz operating frequency. The clock to the DSP is disabled for 1 clock prior

to each edge of the

ΣΔ modulator clock to minimize noise during data conversion. The bit streams from the two ΣΔ converters

are processed through independent data paths within the DSP.

Figure 12. Clock Generation

3.8.2

Decimation Sinc Filter

The serial data stream produced by the

ΣΔ converter is decimated and converted to parallel values by a 3rd order 16:1 sinc

filter with a decimation factor of 8 or 16, depending on the Low Pass Filter selected.

Figure 13. Sinc Filter Response, tS = 8 μs

8 MHz OSC

6 MHz Digital

1MHz Modulator

()

1z 16

–

z 1

–

()

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MMA685X Datasheet(PDF) 25 Page - Freescale Semiconductor, Inc