L3GD20TR datasheet(27/44 Pages) STMICROELECTRONICS

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L3GD20

Digital interfaces

Doc ID 022116 Rev 1

27/44

5.2.2

SPI write

Figure 15.

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: MS bit. When 0, do not increment address; when 1, increment address in multiple

writing.

bit 2 -7: address AD(5:0). This is the address field of the indexed register.

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

first).

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

Figure 16.

Multiple byte SPI write protocol (2-byte example)

5.2.3

SPI read in 3-wire mode

3-wire mode is entered by setting the bit SIM (SPI serial interface mode selection) to ‘1’ in

CTRL_REG2.

SPC

SDI

DI7

D I6 DI5

D I4 DI3

DI2

DI1 DI0

AD5 AD 4 AD 3 AD2 AD 1 AD0

AM10132V1

SPC

SDI

AD5 AD4 AD3 AD2 AD1 AD 0

DI7 D I6 DI5 D I4 DI3 DI2 DI1 DI0 DI15 D I1 4DI13 DI12DI11 DI10 DI9 DI8

AM10133V1

L3GD20TR Datasheet(PDF) 27 Page - STMicroelectronics