VL53L8CX LPn pin ignored

[1MHz]

I have 5 VL53L8CX on the same I2C bus.

I need to set the LPn pin HIGH of the sensor I want to change address.

But the problem is that I can also change the address when LPn pin is low as well.

Also I also don't know how to scan I2C addresses in only one sensor when all other also reply as well even though only one sensor has LPn pin set to HIGH.

Can I not disable I2C with the LPn pin or am I missing something?

LPn pin datasheet:

Enables communication. Drive this pin to logic 0
to disable the I²C communication. Drive this pin
to logic 1 to enable the I²C communication. This
pin is typically used when you need to change
the I²C address in multidevice systems.

 

[Peter BENSCH]

Welcome @1MHz, to the community!

You will find an answer to your question including a step-by-step procedure in UM3109, section 2.3 (under fig. 5).

Hope that helps?

Regards
/Peter

[1MHz]

That procedure is valid after hard reset. But after each sensor is configured with new I2C address and downloaded with firmware the LPn pin can not disable I2C communication anymore.

[John E KVAM]

Once you lift the LPn pin and re-configure the I2C address, you have to leave the LPn pin high. Dropping it means you have to start over. Whenever that pin comes high it will respond on the default I2C address. (The pin actually drops power to the core that does the I2C. So, cycling that pin is rebooting the I2C interface.)