AN3308 datasheet(27/52 Pages) STMICROELECTRONICS

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AN3308

6D/4D orientation detection

Doc ID 18198 Rev 1

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6D/4D orientation detection

The LIS3DH provides an advanced capability to detect the orientation of the device in the

space, enabling easy implementation of an energy saving procedure and automatic image

rotation for handheld devices.

7.1

6D orientation detection

The 6D orientation direction function can be enabled through AOI and 6D bits of the

INT1_CFG register. When configured for 6D function, the ZH, ZL, YH, YL, XH, and XL bits

of INT1_SRC give information about the value of the acceleration generating the interrupt

when it is greater than the threshold, and about its sign. In more detail:

●

ZH (YH, XH) is 1 when the sensed acceleration is bigger than the threshold in the

positive direction

●

ZL (YL, XL) is 1 when the sensed acceleration is bigger than the threshold in the

negative direction.

Figure 11.

ZH, ZL, YH, YL, XH, and XL behavior

There are two possible configurations for the 6D direction function:

●

6D movement recognition: In this configuration the interrupt is generated when the

device moves from a direction (known or unknown) to a different known direction. The

interrupt is active only for 1/ODR

●

6D position recognition: In this configuration the interrupt is generated when the device

is stable in a known direction. The interrupt is active as long as position is maintained

(Figure 12, (a) and (b)).

Referring to Figure 12, the 6D movement line shows the behavior of the interrupt when the

device is configured for 6D movement recognition on the X and Y axis (INT1_CFG =

0x4Ah), while the 6D position line shows the behavior of the interrupt when the device is

configured for 6D position recognition on the X and Y axis (INT1_CFG = 0xCAh). INT1_THS

is set to 0x21.

Referring to Figure 13, the device has been configured for 6D position function on X, Y, and

Z axes. Table 17 shows the content of the INT1_SRC register for each position.

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