Sensor

Freescale Semiconductor, Inc.

19

MMA65xx

3.1.10

Arming Threshold Registers (ARMT_XP, ARMT_XN, ARMT_YP, ARMT_YN)

The arming threshold registers contain the X-axis and Y-axis positive and negative thresholds to be used by the arming func-

tion. Refer to Section 3.8.10 for more details regarding the arming function.

The arming threshold registers can be written during initialization but are locked once the ENDINIT bit is set. Refer to

Section 3.1.6.3. The arming threshold registers are included in the writable register CRC check. Refer to Section 3.2.2 for details.

Table 16. Y-Axis Positive Arming Window Size Definitions (Moving Average Mode)

AWS_YP[1]

AWS_YP[0]

Y-Axis Positive Window Size

00

2

01

4

10

8

11

16

Table 17. Y-Axis Negative Arming Window Size Definitions (Moving Average Mode)

AWS_YN[1]

AWS_YN[0]

Y-Axis Negative Window Size

00

2

01

4

10

8

11

16

Table 18. Arming Count Limit Definitions (Count Mode)

AWS_XN[1]

AWS_XN[0]

AWS_XP[1]

AWS_XP[0]

X-Axis Sample Count Limit

Don’t Care

Don’t Care

0

0

1

Don’t Care

Don’t Care

0

1

3

Don’t Care

Don’t Care

1

0

7

Don’t Care

Don’t Care

1

1

15

Table 19. Arming Count Limit Definitions (Count Mode)

AWS_YN[1]

AWS_YN[0]

AWS_YP[1]

AWS_YP[0]

Y-Axis Sample Count Limit

Don’t Care

Don’t Care

0

0

1

Don’t Care

Don’t Care

0

1

3

Don’t Care

Don’t Care

1

0

7

Don’t Care

Don’t Care

1

1

15

Table 20. Arming Threshold Registers

Location

Bit

Address

Register

7654

3210

$10

ARMT_XP

AT_XP[7]

AT_XP[6]

AT_XP[5]

AT_XP[4]

AT_XP[3]

AT_XP[2]

AT_XP[1]

AT_XP[0]

$11

ARMT_YP

AT_YP[7]

AT_YP[6]

AT_YP[5]

AT_YP[4]

AT_YP[3]

AT_YP[2]

AT_YP[1]

AT_YP[0]

$12

ARMT_XN

AT_XN[7]

AT_XN[6]

AT_XN[5]

AT_XN[4]

AT_XN[3]

AT_XN[2]

AT_XN[1]

AT_XN[0]

$13

ARMT_YN

AT_YN[7]

AT_YN[6]

AT_YN[5]

AT_YN[4]

AT_YN[3]

AT_YN[2]

AT_YN[1]

AT_YN[0]

Reset Value

0000

0000