Sensor

Freescale Semiconductor, Inc.

13

MMA65xx

3.1.1

Device Serial Number Registers

A unique serial number is programmed into the serial number registers of each device during manufacturing. The serial num-

ber is composed of the following information:

Serial numbers begin at 1 for all produced devices in each lot, and are sequentially assigned. Lot numbers begin at 1 and are

sequentially assigned. No lot will contain more devices than can be uniquely identified by the 13-bit serial number. Depending on

lot size and quantities, all possible lot numbers and serial numbers may not be assigned.

The serial number registers are included in the OTP shadow register array CRC verification. Reference Section 3.2.1 for de-

tails regarding the CRC verification. Beyond this, the contents of the serial number registers have no impact on device operation

or performance, and are only used for traceability purposes.

3.1.2

Self Test Deflection Registers (STDEFL_X, STDEFL_Y)

These read-only registers provide the nominal self test deflection values for each axis at ambient temperature. The self test

value is a positive deflection value, measured at the factory, and factory programmed for each device. The minimum stored value

($00) equates to the minimum deflection specified in Section 2.4 (

ΔST

maximum deflection specified in Section 2.4 (

ΔST

When self test is activated, the acceleration reading can be compared to the value in this register. The difference from the

measured deflection value, and the nominal deflection value stored in the register shall not fall outside the self test accuracy limits

specified in Section 2.4 (

ΔST

3.1.3

Factory Configuration Registers

The factory configuration registers are one time programmable, read only registers which contain customer specific device

configuration information that is programmed by Freescale.

Bit Range

Content

S12 - S0

Serial Number

S31 - S13

Lot Number

Table 4. Self Test Deflection Registers

Location

Bit

Address

Register

76

5432

10

$04

STDEFL_X

STDEFL_X[7]

STDEFL_X[6]

STDEFL_X[5]

STDEFL_X[4]

STDEFL_X[3]

STDEFL_X[2]

STDEFL_X[1]

STDEFL_X[0]

$05

STDEFL_Y

STDEFL_Y[7]

STDEFL_Y[6]

STDEFL_Y[5]

STDEFL_Y[4]

STDEFL_Y[3]

STDEFL_Y[2]

STDEFL_Y[1]

STDEFL_Y[0]

Table 5. Factory Configuration Register

Location

Bit

Address

Register

7654

3210

$06

FCTCFG_X

1000

0001

$07

FCTCFG_Y

1000

0001