LPS22DF datasheet(26/54 Pages) STMICROELECTRONICS

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7.3.2

SPI write

Figure 19. SPI write protocol

SPC

SDI

DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0

AD5 AD4 AD3 AD2 AD1 AD0

AD6

The SPI write command is performed with 16 clock pulses. The multiple byte write command is performed by

adding blocks of 8 clock pulses to the previous one.

bit 0: WRITE bit. The value is 0.

bit 1-7: address AD(6:0). This is the address field of the indexed register.

bit 8-15: data DI(7:0) (write mode). This is the data that is written in the device (MSb first).

bit 16-...: data DI(...-8). Further data in multiple byte writes.

Figure 20. Multiple byte SPI write protocol (2-byte example)

SPC

SDI

AD5 AD4 AD3 AD2 AD1 AD0

DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8

AD6

7.3.3

SPI read in 3-wire mode

A 3-wire mode is entered by setting bit SIM to ‘1’ (SPI serial interface mode selection) in CTRL_REG1 (10h).

Figure 21. SPI read protocol in 3-wire mode

SPC

SDI/O

DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0

AD5 AD4 AD3 AD2 AD1 AD0

AD6

The SPI read command is performed with 16 clock pulses:

bit 0: READ bit. The value is 1.

bit 1-7: address AD(6:0). This is the address field of the indexed register.

bit 8-15: data DO(7:0) (read mode). This is the data that is read from the device (MSb first). A multiple read

command is also available in 3-wire mode.

LPS22DF

SPI bus interface (CS = low)

DS13316 - Rev 1

page 26/54

LPS22DF Arkusz danych(PDF) 26 Page - STMicroelectronics