What if BMP581 CSB pin it tied LOW (VSS, VSSIO)?

[BWX]

Regarding BMP581 data sheet v1.2, in section 5.1 for I2C communications it recommends hard-wiring CSB to VDDIO. Later in that section it describes disabling I2C if CSB transitions, which it would not if hard-wired. In section 6.2.3 I2C wiring diagram, it states CSB can be connected to VDDIO or VSSIO. Can operation be described when CSB is tied to VSSIO?

[BSTRobin]

Hi BWX,

What is the hardware communication interface you used? I2C, I3C, SPI?

[FAE_CA1 · Accepted solution]

Hi BWX,

Thanks for your inquiry.

If BMP581 CSB pin is tied LOW (VSS, VSSIO), then neither SPI nor I2C/I3C interface will work.

BMP581 CSB pin has internal pull-up resistor. For I2C or I3C interface, CSB pin needs to be tied to VDDIO by either hard-wiring to VDDIO with internal pull-up resistor disabled or enabling the internal pull-up resistor without being tied to VDDIO. Therefore, BMP581 datasheet Section 6.2.3 has a typo. It says << Leave open (trim_i2c_csb_pup_en = b1) or connect to VDDIO or VSSIO (trim_i2c_csb_pup_en = b0)>>. It should be << Leave open (trim_i2c_csb_pup_en = b1) or connect to VDDIO (trim_i2c_csb_pup_en = b0)>>. We will fix the typo in the new version of BMP581 datasheet.

Thanks.

[BWX]

The target interface is I2C.

[BWX]

That explains it, thanks!