MMA8451Q

Sensors

Freescale Semiconductor, Inc.

39

0x27: PULSE_LTCY Pulse Latency Timer Register

The bits LTCY7 through LTCY0 define the time interval that starts after the first pulse detection. During this time interval, all

pulses are ignored. Note: This timer must be set for single pulse and for double pulse.

The minimum time step for the pulse latency is defined in Table 53 and Table 54. The maximum time is the time step at the ODR

and Oversampling mode multiplied by 255. The timing also changes when the Pulse LPF is enabled or disabled.

Table 51. Time Step for PULSE Time Limit (Reg 0x0F) Pulse_LPF_EN = 0

ODR (Hz)

Max Time Range (s)

Time Step (ms)

Normal

LPLN

HighRes

LP

Normal

LPLN

HighRes

LP

800

0.159

0.159

0.159

0.159

0.625

0.625

0.625

0.625

400

0.159

0.159

0.159

0.319

0.625

0.625

0.625

1.25

200

0.319

0.319

0.159

0.638

1.25

1.25

0.625

2.5

100

0.638

0.638

0.159

1.28

2.5

2.5

0.625

5

50

1.28

1.28

0.159

2.55

5

5

0.625

10

12.5

1.28

5.1

0.159

10.2

5

20

0.625

40

6.25

1.28

5.1

0.159

10.2

5

20

0.625

40

1.56

1.28

5.1

0.159

10.2

5

20

0.625

40

0x27: PULSE_LTCY Register (Read/Write)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

LTCY7

LTCY6

LTCY5

LTCY4

LTCY3

LTCY2

LTCY1

LTCY0

Table 52. PULSE_LTCY Description

LTCY[7:0]

Latency Time Limit. Default value: 0000_0000

Table 53. Time Step for PULSE Latency @ ODR and Power Mode (Reg 0x0F) Pulse_LPF_EN = 1

ODR (Hz)

Max Time Range (s)

Time Step (ms)

Normal

LPLN

HighRes

LP

Normal

LPLN

HighRes

LP

800

0.638

0.638

0.638

0.638

2.5

2.5

2.5

2.5

400

1.276

1.276

1.276

1.276

5555

200

2.56

2.56

1.276

2.56

10

10

5

10

100

5.1

5.1

1.276

5.1

20

20

5

20

50

10.2

10.2

1.276

10.2

40

40

5

40

12.5

10.2

40.8

1.276

40.8

40

160

5

160

6.25

10.2

40.8

1.276

81.6

40

160

5

320

1.56

10.2

40.8

1.276

81.6

40

160

5

320

Table 54. Time Step for PULSE Latency @ ODR and Power Mode (Reg 0x0F) Pulse_LPF_EN = 0

ODR (Hz)

Max Time Range (s)

Time Step (ms)

Normal

LPLN

HighRes

LP

Normal

LPLN

HighRes

LP

800

0.318

0.318

0.318

0.318

1.25

1.25

1.25

1.25

400

0.318

0.318

0.318

0.638

1.25

1.25

1.25

2.5

200

0.638

0.638

0.318

1.276

2.5

2.5

1.25

5

100

1.276

1.276

0.318

2.56

5

5

1.25

10

50

2.56

2.56

0.318

5.1

10

10

1.25

20

12.5

2.56

10.2

0.318

20.4

10

40

1.25

80

6.25

2.56

10.2

0.318

20.4

10

40

1.25

80

1.56

2.56

10.2

0.318

20.4

10

40

1.25

80