LSM330D Datasheet, PDF (32/66 Pages) STMicroelectronics – Low power mode

Digital interfaces
6
Digital interfaces
LSM330D
The registers embedded in the LSM330D may be accessed through both the I²C and SPI
serial interfaces. The latter may be SW configured to operate either in 3-wire or 4-wire
interface mode.
To select/exploit the I²C interface, the CS line must be tied high (i.e. connected to Vdd_IO).
Table 10. Serial interface pin description
Pin name
Pin description
CS_A
Linear acceleration SPI enable
Linear acceleration I²C/SPI mode selection (1: I²C mode; 0: SPI enabled)
CS_G
SCL_A/G
SDA_A/G
SDO_A
SDO_G
Angular rate SPI enable
Angular rate I²C/SPI mode selection (1: I²C mode; 0: SPI enabled)
I²C serial clock (SCL)
SPI serial port clock (SPC)
I²C serial data (SDA)
SPI serial data input (SDI)
3-wire interface serial data output (SDO)
I²C least significant bit of the device address (SA0)
SPI serial data output (SDO)
6.1
I²C serial interface
The LSM330D I²C is a bus slave. The I²C is employed to write the data to the registers,
whose content can also be read back.
The relevant I²C terminology is provided in the table below.
Table 11. Serial interface pin description
Term
Description
Transmitter
The device which sends data to the bus
Receiver
The device which receives data from the bus
Master
The device which initiates a transfer, generates clock signals and terminates a
transfer
Slave
The device addressed by the master
There are two signals associated with the I²C bus: the Serial Clock Line (SCL) and the
Serial DAta line (SDA). The latter is a bidirectional line used for sending and receiving the
data to/from the interface.
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Doc ID 022562 Rev 2