ADIS16266 Просмотр технического описания (PDF) - Analog Devices

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ADIS16266

±14,000°/sec Digital Gyroscope Sensor

Analog Devices 

Data Sheet

THEORY OF OPERATION

The ADIS16266 integrates a MEMS gyroscope with data

sampling, signal processing, and calibration functions, along

with a simple user interface. This sensing system collects data

autonomously and makes it available to any processor system

that supports a 4-wire serial peripheral interface (SPI).

SENSING ELEMENT

The sensing element operates on the principle of a resonator gyro.

Two polysilicon sensing structures each contain a dither frame

that is electrostatically driven to resonance, producing the necessary

velocity element to generate a Coriolis force during angular rate. At

two of the outer extremes of each frame, orthogonal to the dither

motion, movable fingers are placed between fixed pickoff

fingers to form a capacitive pickoff structure that senses Coriolis

motion. The resulting signal is fed into a series of gain and

demodulation stages that produce the electrical rate signal

output. The differential structure minimizes the response to

linear acceleration (gravity, vibration, and so on) and EMI.

DATA SAMPLING AND PROCESSING

The ADIS16266 runs autonomously, based on the configuration

in the user control registers. The analog gyroscope signal feeds

into an analog-to-digital converter (ADC) stage, which passes

digitized data into the controller for data processing and register

loading. Data processing in the embedded controller includes

correction formulas, filtering, and checking for preset alarm

conditions. The correction formulas are unique for each individual

ADIS16266 and come from the factory characterization of each

device over a temperature range of −40°C to +70°C.

ADIS16266

MEMS

SENSOR

OUTPUT

REGISTERS

TEMP

SENSOR

AIN

SIGNALS

ADC

CONTROLLER

CONTROL

REGISTERS

CLOCK

Figure 9. Simplified Sensor Signal Processing Diagram

USER INTERFACE

SPI Interface

Data collection and configuration commands both use the SPI,

which consists of four wires. The chip select (CS) signal activates

the SPI interface, and the serial clock (SCLK) signal synchronizes

the serial data lines. The serial input data clocks into DIN on

the SCLK rising edge, and the serial output data clocks out of

DOUT on the SCLK falling edge. Many digital processor platforms

support this interface with dedicated serial ports and simple

instruction sets.

User Registers

The user registers provide addressing for all input/output operations

on the SPI interface. Each 16-bit register has its own unique bit

assignment and has two 7-bit addresses: one for its upper byte

and one for its lower byte. Table 7 provides a memory map of

the user registers, along with the function of each register.

Rev. A | Page 9 of 24

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