LPS001WP Datasheet, PDF (16/30 Pages) STMicroelectronics – MEMS pressure sensor 300-1100 mbar absolute digital output barometer

Digital interfaces
LPS001WP
Figure 4. Read and write protocol
CS
SPC
SDI
SDO
RW
DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0
MS AD5 AD4 AD3 AD2 AD1 AD 0
DO 7 DO6 DO5 DO 4 DO3 DO2 DO1DO0
CS is the serial port enable and it is controlled by the SPI master. It goes low at the start of
) _{the transmission and returns to high at the end. SPC is the serial port clock and it is}
t(s ^{controlled by the SPI master. It is stopped high when CS is high (no transmission). SDI and}
c SDO are respectively the serial port data input and output. Those lines are driven at the
u _{falling edge of SPC and should be captured at the rising edge of SPC.}
rod ^{Both the read register and write register commands are completed in 16 clock pulses or in}
multiples of 8 in the case of multiple byte read/write. Bit duration is the time between two
P _{falling edges of SPC. The first bit (bit 0) starts at the first falling edge of SPC after the falling}
te _{edge of CS while the last bit (bit 15, bit 23, ...) starts at the last falling edge of SPC just}
le before the rising edge of CS.
bso _{bit 0: RW bit. When 0, the data DI(7:0) is written into the device. When 1, the data DO(7:0)}
O _{from the device is read. In the latter case, the chip drives SDO at the start of bit 8.}
) ^- _{bit 1: MS bit. When 0, the address remains unchanged in multiple read/write commands.}
t(s ^{When 1, the address is auto incremented in multiple read/write commands.}
c _{bit 2-7: address AD(5:0). This is the address field of the indexed register.}
du _{bit 8-15: data DI(7:0) (write mode). This is the data that is written into the device (MSb first).}
ro _{bit 8-15: data DO(7:0) (read mode). This is the data that is read from the device (MSb first).}
te ^{P In multiple read/write commands further blocks of 8 clock periods are added. When the MS}
le^{bit is 0, the address used to read/write data remains the same for every block. When MS bit}
is 1, the address used to read/write data is incremented at every block.
Obso ^{The function and the behavior of SDI and SDO remain unchanged.}
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Doc ID 18171 Rev 1