BMX160 SDO pin floating in I2C setup

[timmbo]

Hey all,

we have a BMX160 integrated into one of our hardware designs. We use the I2C interface. Just by accident we found that the SDO pin is floating, although it should be tied to either GND or VDDIO for the address selection (says the datasheet). The address seems to default to 0x69. Is there an internal pull-up on SDO and is it generally possible to leave the pin floating when using the I2C interface?

Thanks in advance

[BSTRobin]

Hi timmbo,

1.If you are designing PCB, it is recommended that you connect the SDO pin to GND and provide a certain level to the pin.

2.Who told you 0x69 address when SDO (pin 1) is floating?

[timmbo]

Hey BSTRobin,

1. Okay, understood. Our hardware is mass-produced already, so we can't change it at the moment. But for future development we will consider it.

2. Nobody told us, we just found that the BMX160 is only responding on 0x69 when SDO is floating. I assume SDO is internally pulled-up?

Best

[BSTRobin · Accepted solution]

Hi timmbo,

SDO pin has no internal pull-up resistance.
When setting BMX160 SDO pin floating, SDO pin status(high or low level) is uncertain, and it is not recommended to use it this way. It is recommended to give the SDO pin a certain level.