LPS22HB Digital interfaces
The registers embedded in the LPS22HB 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
CS line must be tied high (i.e. connected to Vdd_IO).
Pin name
CS
SCL/SPC
SDA
SDI
SDI/SDO
SDO
SAO
Table 9. Serial interface pin description
Pin description
SPI enable
I²C/SPI mode selection (1: SPI idle mode / I
2
C communication enabled; 0: SPI communication mode / I
2
C disabled)
I²C serial clock (SCL)
SPI serial port clock (SPC)
I²C serial data (SDA)
4-wire SPI serial data input (SDI)
3-wire serial data input /output (SDI/SDO)
SPI serial data output (SDO)
I²C less significant bit of the device address (SA0)
7.2 I
2
C serial interface (CS = High)
The LPS22HB 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
Table 10.
Term
Table 10. I 2 C terminology
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. 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.
DocID027083 Rev 6 25/49
49
