LIS2MDL datasheet(25/41 Pages) STMICROELECTRONICS

25 / 41 page

DocID030621 Rev 5

25/41

LIS2MDL

Digital interfaces

6.2

SPI bus interface

The LIS2MDL SPI is a bus slave. The SPI allows writing and reading the registers of the

device.

The default serial interface interacts with the application using 3 wires: CS, SPC, SDI/O.

The 4-wire SPI interface mode can be activated by writing bit 2 of CFG_REG_C (62h) to 1.

Of course, doing this disables the interrupt and data-ready signaling capability of the device.

6.2.1

SPI write

Figure 6. SPI write protocol

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 inside the device (MSb

first).

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

Figure 7. Multiple byte SPI write protocol (2-byte example)

SPC

SDI

D I7D I6

D I5D I4

DI3DI2

DI1DI0

AD5 AD 4 AD 3 AD2 AD 1 AD0

AD6

SPC

SDI

AD5 AD4 AD3 AD2 AD1 AD 0

DI7 D I6 DI5 D I4 DI3 DI2 DI1 DI0 DI15 D I1 4 DI13 D I1 2 DI11 DI10 DI9 DI8

AD6

LIS2MDL Datasheet(PDF) 25 Page - STMicroelectronics