Sensors

17

Freescale Semiconductor, Inc.

MMA7660FC

$07: Mode Register (Read/Write)

MODE

NOTE: Writing to the Mode register resets sleep timing, and clears the XOUT, YOUT, ZOUT, TILT registers.Reading to

the Mode register resets sleep timing.

NOTE: The device must be placed in Standby Mode to change the value of the registers.

NOTE: The device can only enter into Test Mode, when the previous mode was Standby Mode. If the device was in

Active mode, set MMA766FC to Standby Mode (MODE = TON = 0), then enter Test Mode (MODE = 0, TON = 1).

MODE

0: Standby mode or Test Mode depending on state of TON

1: Active mode

Existing state of TON bit must be 0, to write MODE = 1. Test

Mode must not be enabled.

MMA7660FC always enters Active Mode using the samples

per second specified in AMSR[2:0] of the SR (0x08) register.

When MMA7660FC enters Active Mode with

[ASE:AWE] = 11, MMA7660FC operates Auto-Sleep

functionality first.

TON

0: Standby Mode or Active Mode depending on state of

MODE

1: Test Mode

Existing state of MODE bit must be 0, to write TON = 1.

Device must be in Standby Mode.

In Test Mode (TON = 1), the data in the XOUT, YOUT and

ZOUT registers is not updated by measurement, but is

purposes. Changes to the XOUT, YOUT and ZOUT register

data is processed by MMA7660FC to change orientation

status and generate interrupts just like Active Mode.

Debounce filtering and shake detection are disabled in Test

Mode.

AWE

0: Auto-Wake is disabled

1: Auto-Wake is enabled.

When Auto-Wake functionality is operating, the AWSRS bit is

the SRST register is set and the device uses the samples per

second specified in AWSR[1:0] of the SR (0x08) register.

When MMA7660FC automatically exits Auto-Wake by a

selected interrupt, the device will then switch to the samples

per second specified in AMSR[2:0] of the SR (0x08) register.

If ASE = 1, then Auto-Sleep functionality is now enabled

(Table 11).

ASE

0: Auto-Sleep is disabled

1: Auto-Sleep is enabled

When Auto-Sleep functionality is operating, the AMSRS bit is

the SRST register is set and the device uses the samples per

second specified in AMSR[2:0] of the SR (0x08) register.

When MMA7660FC automatically exits Auto-Sleep because

the Sleep Counter times out, the device will then switch to the

samples per second specified in AWSR[1:0] of the SR

register. If AWE = 1, then Auto-Wake functionality is now

enabled (Table 11).

SCPS

0: The prescaler is divide-by-1. The 8-bit internal Sleep

Counter input clock is the samples per second set by

AMSR[2:0], so the clock range is 120 Hz to 1 Hz depending

on AMSR[2:0] setting. Sleep Counter timeout range is

256 times the prescaled clock (see Table 12).

1: Prescaler is divide-by-16. The 8-bit Sleep Counter input

clock is the samples per second set by AMSR[2:0] divided by

16, so the clock range is 4 Hz to 0.0625 Hz depending on

AMSR[2:0] setting. Sleep Counter timeout range is 256 times

the prescaled clock (see Table 12).

IPP

0: Interrupt output INT is open-drain.

1: Interrupt output INT is push-pull

NOTE: Do NOT connect pull-up resistor from INT to

higher voltage than DVDD.

IAH

0: Interrupt output INT is active low

1: Interrupt output INT is active high

The active interrupt condition (IRQ = 0 if IAH = 0, IRQ = 1 if IAH = 1) is released during the acknowledge bit of the slave address

D7

D6

D5

D4

D3

D2

D1

D0

IAH

IPP

SCPS

ASE

AWE

TON

-

MODE

0

000

0000

Table 10. Modes

Mode of Operation

D0 - MODE

D2 - TON

Standby Mode

0

0

Test Mode

0

1

Active Mode

1

0