Sensors

30

Freescale Semiconductor, Inc.

MMA16xxKW

4.2.1.1

Initialization Command

The initialization command conforms to the description provided in Section 6.1.1 of the DSI Bus Standard V2.5. The initializa-

tion command is only supported as a standard long command. No other commands are recognized by the device until a valid

standard long initialization command is received.

of a DSI Initialization command. The BUSOUT node is tested for a bus short to high voltage condition, and the bus fault (BF) flag

is set if an error condition is detected. If no bus fault condition is detected and the BS bit is set in the Initialization command mes-

cover following closure of the bus switch.

If the device has been preprogrammed, PA[3:0] and A[3:0] must match the preprogrammed address.

If no device address has been previously programmed into the OTP array, PA[3:0] contains the device address, and A[3:0]

must be zero. If either addressing condition is not met, the device address is not assigned, the bus switch will remain open and

the device will not respond to the Initialization command. If the addressing conditions are met, the new device address is as-

signed to A[3:0]. Once the device address is assigned, the new address (A[3:0]) is not protected by the User Programmable OTP

Array CRC Verification. The User Programmable OTP array CRC is calculated and verified using the OTP programmed values

of A[3:0] = ‘0000’.

Once initialized, the device will no longer recognize or respond to Initialization commands.

Table 12. Initialization Command

Data

Address

Command

CRC

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

A[3]

A[2]

A[1]

A[0]

C[3]

C[2]

C[1]

C[0]

NV

BS

Bnk[1]

Bnk[0]

PA[3]

PA[2]

PA[1]

PA[0]

A[3]

A[2]

A[1]

A[0]

0000

4 bits

Table 13. Initialization Command Bit Definitions

Bit Field

Definition

C[3:0]

Initialization Command = ‘0000’

A[3:0]

DSI device address. This address is set to the preprogrammed device address following reset, or to ‘0000’ if no preprogrammed address

has been assigned.

PA[3:0]

DSI Address to be programmed.

Bnk[1:0]

These bits select the bank address for the user writable data registers. Bank selection affects the Read/Write NVM command operation.

Invalid combinations of B1 and B0 result in no response from the device to the associated initialization. Refer to Section 4.2.1.10 for fur-

ther details regarding register programming and bank selection.

BS

Bus Switch state. This bit controls the state of the DSI bus switch.

1 - Close the bus switch.

0 - Do not close the bus switch.

NV

NVM Program Enable. This bit enables programming of the user-programmed OTP locations. Data to be programmed is transferred to the

device during subsequent Read Write NVM commands.

1 - Enable OTP programming

0 - Disable OTP programming

Table 14. Initialization Command Response

Response

CRC

D[15]

D[14]

D[13]

D[12]

D[11]

D[10]

D[9]

D[8]

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

PA[3]

PA[2]

PA[1]

PA[0]

0

0

0

BF

NV

BS

Bnk[1]

Bnk[0]

PA[3]

PA[2]

PA[1]

PA[0]

4 bits