Terminology & functionality

L2G2IS

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DocID027248 Rev 2

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Terminology & functionality

2.1

Sensitivity

An angular rate gyroscope is a device that produces a positive-going digital output for

counterclockwise rotation around the sensitive axis considered. Sensitivity describes the

gain of the sensor and can be determined by applying a defined angular velocity to it. This

value changes very little over temperature and time.

2.2

Zero-rate level

The zero-rate level describes the actual output signal if there is no angular rate present. The

zero-rate level of highly accurate MEMS sensors is, to some extent, a result of stress to the

sensor and therefore the zero-rate level can slightly change after mounting the sensor on a

printed circuit board or after exposing it to extensive mechanical stress. This value changes

very little over temperature and time.

2.3

Data-ready interrupt and synchronous reading

On the L2G2IS the angular rate data can be retrieved using a synchronous read. To perform

a synchronous read, CTRL_REG3 (0Dh) (DRDY_EN) has to be set to '1' in order to enable

the data-ready interrupt on the DRDY pin (refer to Figure 4). To properly perform a

synchronous read, the angular rate data have to be read every time the DRDY pin goes

high.

The DRDY signal can be latched (default condition) or pulsed if the CTRL_REG1 (0Bh)

(P_DRDY) is set to ‘1’. When a latched condition is selected, the interrupt goes low when

the high part of one of the output channels is read (OUT_X_H (04h) or OUT_Y_H (06h)) and

returns high when new data is generated. When a pulsed condition is selected, the interrupt

behavior is independent from the reading operations and remains high for 75 μsec every

time new data is generated. The DRDY pin is set by default as push-pull output, but it can

be configured as open-drain output by setting CTRL_REG3 (0Dh) (PP_OD) to ‘1’.

2.4

Temperature sensor

The temperature data can be retrieved from the TEMP_OUT_L (01h), TEMP_OUT_H (02h)

register, as two’s complement data in 12-bit format left-justified. The output of the

temperature sensor is 0 at 25 °C.