LSM9DS1 Datasheet, PDF (37/72 Pages) –

LSM9DS1
Digital interfaces
5.3.3
SPI read in 3-wire mode
3-wire mode is entered by setting the SIM bit to ‘1’ (SPI serial interface mode selection) in
CTRL_REG3_M (22h).
When 3-wire mode is used, the SDO_M pin has to be connected to GND or Vdd_IO.
Figure 27. SPI read protocol in 3-wire mode
CS_C__SM
SPC
SDI/O
RW
D O7 D O6 D O5 DO4 DO3 DO2 DO1 DO0
MS AD5 AD 4 AD 3 AD2 AD1 AD 0
The SPI read command is performed with 16 clock pulses:
bit 0: READ bit. The value is 1.
bit 1: MS bit. When 0, does not increment the address; when 1, increments the address in
multiple reads.
bit 2-7: address AD(5:0). 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.
DocID025715 Rev 3
37/72
72