Sensors

Freescale Semiconductor

3

MMA8451Q

6

Register Descriptions .......................................................................................................................................................21

Table 11. Register Address Map ...............................................................................................................................21

6.1

Data Registers ...........................................................................................................................................................22

F_MODE = 00: 0X00 STATUS: Data Status Register (Read Only) ....................................................................22

Table 12. STATUS Description .................................................................................................................................23

Data Registers: 0x01 OUT_X_MSB, 0x02 OUT_X_LSB, 0x03 OUT_Y_MSB, 0X04 OUT_Y_LSB ............................24

0x01 OUT_X_MSB: X_MSB Register (Read Only) .............................................................................................24

0x02 OUT_X_LSB: X_LSB Register (Read Only) ...............................................................................................24

0x03 OUT_Y_MSB: Y_MSB Register (Read Only) .............................................................................................24

0x04 OUT_Y_LSB: Y_LSB Register (Read Only) ...............................................................................................24

0x05 OUT_Z_MSB: Z_MSB Register (Read Only) .............................................................................................24

0x06 OUT_Z_LSB: Z_LSB Register (Read Only) ...............................................................................................24

6.2

32 Sample FIFO ........................................................................................................................................................24

F_MODE > 0 0x00: F_STATUS FIFO Status Register ................................................................................................24

0x00 F_STATUS: FIFO STATUS Register (Read Only) .....................................................................................24

Table 13. FIFO Flag Event Description .....................................................................................................................25

Table 14. FIFO Sample Count Description ...............................................................................................................25

0x09: F_SETUP FIFO Set-up Register ........................................................................................................................25

0x09 F_SETUP: FIFO Set-up Register (Read/Write) ..........................................................................................25

Table 15. F_SETUP Description ...............................................................................................................................25

0x0A: TRIG_CFG .........................................................................................................................................................26

0x0A: TRIG_CFG Trigger Configuration Register (Read/Write) ..........................................................................26

Table 16. Trigger Configuration Description ..............................................................................................................26

0x0B: SYSMOD System Mode Register ......................................................................................................................26

0x0B SYSMOD: System Mode Register (Read Only) .........................................................................................26

Table 17. SYSMOD Description ................................................................................................................................26

0x0C: INT_SOURCE System Interrupt Status Register ...............................................................................................27

Table 18. INT_SOURCE Description ........................................................................................................................27

0x0D: WHO_AM_I Device ID Register .........................................................................................................................28

0x0D: WHO_AM_I Device ID Register (Read Only) ............................................................................................28

0x0E: XYZ_DATA_CFG Register ................................................................................................................................28

0x0E: XYZ_DATA_CFG (Read/Write) .................................................................................................................28

Table 19. XYZ Data Configuration Descriptions ........................................................................................................28

Table 20. Full Scale Range .......................................................................................................................................28

0x0F: HP_FILTER_CUTOFF High Pass Filter Register ..............................................................................................28

0x0F HP_FILTER_CUTOFF: High Pass Filter Register (Read/Write) ................................................................28

Table 21. High Pass Filter Cut-off Register Descriptions ..........................................................................................28

Table 22. High Pass Filter Cut-off Options ................................................................................................................29

6.3

Portrait/ Landscape Embedded Function Registers ..................................................................................................29

0x10: PL_STATUS Portrait/Landscape Status Register ..............................................................................................29

0x10 PL_STATUS Register (Read Only) ............................................................................................................29

Table 23. PL_STATUS Register Description ............................................................................................................29

0x11 Portrait/Landscape Configuration Register .........................................................................................................30

0x11 PL_CFG Register (Read/Write ...................................................................................................................30

Table 24. PL_CFG Description .................................................................................................................................30

0x12 Portrait/Landscape Debounce Counter ...............................................................................................................30

0x12 PL_COUNT Register (Read/Write) .............................................................................................................30

Table 25. PL_COUNT Description ............................................................................................................................30

Table 26. PL_COUNT Relationship with the ODR ....................................................................................................30

0x13: PL_BF_ZCOMP Back/Front and Z Compensation Register ..............................................................................30

0x13: PL_BF_ZCOMP Register (Read/Write) .....................................................................................................30

Table 27. PL_BF_ZCOMP Description .....................................................................................................................30

Table 28. Z-Lock Threshold Angles ..........................................................................................................................31

Table 29. Back/Front Orientation Definition ..............................................................................................................31

0x14: P_L_THS_REG Portrait/Landscape Threshold and Hysteresis Register ...........................................................31

0x14: P_L_THS_REG Register (Read/Write) ......................................................................................................31

Table 30. P_L_THS_REG Description ......................................................................................................................31

Table 31. Threshold Angle Thresholds Look-up Table .............................................................................................31

Table 32. Trip Angles with Hysteresis for 45° Angle .................................................................................................31