lis3l02ds STMicroelectronics, lis3l02ds Datasheet - Page 9

• Manufacturer Part Number: lis3l02ds
• Description: Three Axis 2g-6g Linear Accelerometer
• Manufacturer: STMicroelectronics

2.2 SPI Bus Interface
The Gengine SPI is a bus slave. The SPI allows to write and read the registers of the device.
The Serial Interface interacts with the outside world with 4 wires: CS, SPC, SPDI and SPDO.
2.2.1 Read & Write registers
Figure 2. Read & write protocol
CS is the Serial Port Enable and it is controlled by the SPI master. It goes low at the start of the transmis-
sion and goes back high at the end. SPC is the Serial Port Clock and it is controlled by the SPI master. It
is stopped high when CS is high (no transmission). SPDI and SPDO are respectively the Serial Port Data
Input and Output. Those lines are driven at the falling edge of SPC and should be captured at the rising
edge of SPC.
Both the Read Register and Write Register commands are completed in 16 clocks pulses. Bit duration is
the time between two falling edges of SPC. The first bit (bit 0) starts at the first falling edge of SPC after
the falling edge of CS while the last bit (bit 15) starts at the last falling edge of SPC just before the rising
edge of CS.
– bit 0: RW bit. When 0, the data DI(7:0) is written into the device. When 1, the data DO(7:0) from the
– 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 will be written into the device (MSb first).
– bit 8-15: data DO(7:0) (read mode). This is the data that will be read from the device (MSb first).
device is read. In latter case, the chip will drive SPDO at the start of bit 8.
SPDO
SPDI
SPC
CS
RW
AD6 AD5 AD4 AD3 AD2 AD1 AD0
DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0
DI7
DI6
DI5
DI4
DI3
DI2
DI1
DI0
LIS3L02DS
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