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Bosch Sensortec | BMP280 Data sheet

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Document number: BST-BMP280-DS001-26 Revision_1.26_102021

5.2.2

I²C read

To be able to read registers, first the register address must be sent in write mode (slave address

111011X0). Then either a stop or a repeated start condition must be generated. After this the slave is

addressed in read mode (RW = ‘1’) at address 111011X1, after which the slave sends out data from

auto-incremented register addresses until a NOACKM and stop condition occurs. This is depicted in

Figure 8

, where two bytes are read from register 0xF6 and 0xF7.

Start

RW ACKS

ACKS

Start

RW ACKS

ACKM

NOACKM Stop

bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0

Control byte

Data byte

Slave Address

Figure 8: I²C multiple byte read

5.3 SPI interface

The SPI interface is compatible with SPI mode ‘00’ (CPOL = CPHA = ‘0’) and mode ‘11’ (CPOL =

CPHA = ‘1’). The automatic selection between mode ‘00’ and ‘11’ is determined by the value of SCK

after the CSB falling edge.

The SPI interface has two modes: 4-wire and 3-wire. The protocol is the same for both. The 3-wire

mode is selected by setting ‘1’ to the register spi3w_en. The pad SDI is used as a data pad in 3-wire

mode.

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