Data Sheet

Digital interfaces LPS25HB

24/50 DocID027112 Rev 4

6 Digital interfaces

6.1 I

C serial interface

The registers embedded in the LPS25HB 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.

The serial interfaces are mapped onto the same pads. To select/exploit the I²C interface, the

line must be tied high (i.e. connected to Vdd_IO);

to select the SPI interface, the CS line

must be tied low (i.e. connected to GND).

6.2 I

C serial interface (CS = High)

The LPS25HB I²C is a bus slave. The I²C is employed to write data into registers whose

content can also be read back.

The relevant I²C terminology is given in Ta b l e 9

There are two signals associated with the I²C bus: the serial clock line (SCL) and the serial

data line (SDA). The latter is a bi-directional line used for sending and receiving the data

to/from the interface. Both lines have to be connected to Vdd_IO through pull-up resistors.

The I²C interface is compliant with fast mode (400 kHz) I²C standards as well as with the

normal mode.

Table 10. Serial interface pin description

Pin name Pin

SPI enable

I²C/SPI mode selection (1: I²C mode; 0: SPI enabled

SCL/SPC

I²C serial clock (SCL)

SPI serial port clock (SPC)

SDA

SDI

SDI/SDO

I²C serial data (SDA)

4-wire SPI serial data input (SDI)

3-wire serial data input /output (SDI/SDO)

SDO

SAO

SPI serial data output (SDO)

I²C less significant bit of the device address (SA0)

Table 11.

C terminology

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