Datasheet

BMP280 Digital Pressure Sensor

Page 28

BST-BMP280-DS001-19 | Revision 1.19 | January 2018

Bosch Sensortec

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

5. Digital interfaces

The BMP280 supports the I²C and SPI digital interfaces; it acts as a slave for both protocols. The

I²C interface supports the Standard, Fast and High Speed modes. The SPI interface supports

both SPI mode ‘00’ (CPOL = CPHA = ‘0’) and mode ‘11’ (CPOL = CPHA = ‘1’) in 4-wire and 3-

wire configuration.

The following transactions are supported:

 Single byte write

 multiple byte write (using pairs of register addresses and register data)

 single byte read

 multiple byte read (using a single register address which is auto-incremented)

5.1 Interface selection

Interface selection is done automatically based on CSB (chip select) status. If CSB is connected

has been pulled down once (regardless of whether any clock cycle occurred), the I²C interface is

disabled until the next power-on-reset. This is done in order to avoid inadvertently decoding SPI

on-reset of the device. If this is not the case, the device will be locked in SPI mode and not respond

to I²C commands.

5.2 I²C Interface

The I²C slave interface is compatible with Philips I²C Specification version 2.1. For detailed timings

refer to Table 27. All modes (standard, fast, high speed) are supported. SDA and SCL are not

pure open-drain. Both pads contain ESD protection diodes to VDDIO and GND. As the devices

does not perform clock stretching, the SCL structure is a high-Z input without drain capability.

GND

output driver (only for SDI)

SDI /SCL

high-z level shifter

GND

The 7-bit device address is 111011x. The 6 MSB bits are fixed. The last bit is changeable by SDO

value and can be changed during operation. Connecting SDO to GND results in slave address