BME280 datasheet(33/60 Pages) BOSCH

33 / 60 page

Bosch Sensortec | BME280 Data sheet

33 | 60

Modifications reserved | Data subject to change without notice

Document number: BST-BME280-DS001-23 Revision_1.23_012022

BMP280’s I²C address. The SDO pin cannot be left floating; if left floating, the I²C address will be

undefined.

The I²C interface uses the following pins:

•

SCK: serial clock (SCL)

•

SDI:

data (SDA)

•

SDO: Slave address LSB (GND = ‘0’, VDDIO = ‘1’)

CSB must be connected to VDDIO to select I²C interface. SDI is bi-directional with open drain to GND: it

must be externally connected to VDDIO via a pull up resistor. Refer to chapter 7 for connection

instructions.

The following abbreviations will be used in the I²C protocol figures:

•

Start

•

Stop

•

ACKS

Acknowledge by slave

•

ACKM

Acknowledge by master

•

NACKM

Not acknowledge by master

6.2.1

I²C write

Writing is done by sending the slave address in write mode (RW = ‘0’), resulting in slave address

111011X0 (‘X’ is determined by state of SDO pin. Then the master sends pairs of register addresses

and register data. The transaction is ended by a stop condition. This is depicted in Figure 9.

Start

RW ACKS

ACKS

bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0

…

ACKS

ACKS Stop

…

bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0

Slave Address

Control byte

Data byte

Control byte

Data byte

Figure 9: I²C multiple byte write (not auto-incremented)

6.2.2

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 10

, where register 0xF6 and 0xF7 are read.

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 10: I²C multiple byte read

BME280 Datasheet(PDF) 33 Page - Bosch Sensortec GmbH

BME280 Datasheet(HTML) 33 Page - Bosch Sensortec GmbH

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Datasheet Download

Link URL