AN4506 Просмотр технического описания (PDF) - STMicroelectronics

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AN4506

L3GD20H: 3-axis digital output gyroscope

STMicroelectronics 

Reading angular rate data

AN4506

3.2

Using the status register

The device is provided with a STATUS register which should be polled to check when a new

set of data is available. The reading procedure should be the following:

1. Read STATUS

2. If STATUS(3) = 0 then go to 1

3. If STATUS(7) = 1 then some data have been overwritten

4. Read OUT_X_L

5. Read OUT_X_H

6. Read OUT_Y_L

7. Read OUT_Y_H

8. Read OUT_Z_L

9. Read OUT_Z_H

10. Data processing

11. Go to 1

The check performed at step 3 allows the user to understand whether the reading rate is

adequate compared to the data production rate. If one or more angular rate samples have

been overwritten by new data, because of an insufficient reading rate, the ZYXOR bit of the

STATUS register is set to 1.

The overrun bits and the new data available bits are automatically cleared when all the data

present inside the device have been read and new data have not been produced in the

meantime.

3.3

Using the data-ready (DRDY) signal

The device may be configured to have one HW signal to determine when a new set of

measurement data is available for reading. This signal is represented by the XYZDA bit of

the STATUS register. The signal can be driven to the DRDY/INT2 pin by setting the

I2_DRDY bit to 1 in the CTRL3 register and its polarity to active-low or active-high through

the H_Lactive bit of the CTRL3 register (see Section 5.1).

The data-ready signal rises to 1 when a new set of angular rate data has been generated

and is available for reading. The interrupt is reset when the higher part of one of the enabled

channels has been read (29h, 2Bh, 2Dh).

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