Sensors

Freescale Semiconductor, Inc.

27

MMA16xxKW

3.6

Device Initialization

Following powerup, under-voltage reset or reception of a DSI Clear Command, the device proceeds through an initialization

process as described in the following tables:

Figure 20. Initialization Timing

Table 9. Power-up or Under-Voltage Reset Initialization Process

#

Description

Time

S Flag ST Flag

DSI Response

1 Power up to a Known State

0

N/A

N/A

No Response

3 Read Fuse Array and Copy to Memory Array (Mirror Registers)

1

0

No Response

4 Initialize DSI State Machine (the device is ready for DSI Messages)

10

DSI Read Acceleration Data Short response = zero.

DSI Read Acceleration Data Long response = invalid data.

5 Initialize the DSP (Acceleration Data is Valid)

0

0

Normal

Table 10. DSI Clear Command Initialization Process

#

Description

Time

S Flag ST Flag

DSI Response

1 the device logic comes out of reset

0

1

0

No Response

3 Read Fuse Array and Copy to Memory Array (Mirror Registers)

1

0

No Response

4 Initialize DSI State Machine (the device is ready for DSI Messages)

10

DSI Read Acceleration Data Short response = zero.

DSI Read Acceleration Data Long response = invalid data.

5 Initialize the DSP (Acceleration Data is Valid)

0

0

Normal

BUSIN’

DSP_OUT

DSI Ready

POR

Internal Delay