Strange schematic for X-NUCLEO-53L1A1, I2C level shifter

[JWill.12]

Hi,

X-NUCLEO-53L1A1 expansion board uses an IC (ST2329AQTR) to shift the 3.3V I2C bus lines of the MCU to a 2.8V I2C bus for the proximity sensor VL53l1x.

Why are there these strange connections between the 3.3V and 2.8V bus as shown on the schematic of the X-NUCLEO-53L1A1 (see attached file) ?

 

Thanks,

Jeremie

[Miroslav BATEK]

The nominal power supply voltage for VL53I1x is 2.8 V.

[JWill.12]

I'm aware of that. My question is about the i2c level shifter, from 3.3 to 2.8V. Why are the 2 bus connected? What's the point of the level shifter in that case?

[Miroslav BATEK · Accepted solution]

I think the schematic is not correct, the 3.3V and 2.8V buses cannot be connect together (shorted).

Most probably solder bridges are missing in the schematic.

[JWill.12]

Ok, we agree on that.

Thanks