I am working with a VL53L8CX breakout out board from Pololu and having a hard time getting the I2C bus up and running… I have wired up VIN, GND, SCL and SDA from the breakout to an existing (and working) I2C bus. This unfortunately breaks the bus… The symptoms are kind of hard to describe… I am looking at the bus with a saleae and I am seeing the SDA jump from low to high approximate every 300ns and SCL is dipping from high to low randomly. I am looking at the schematic and wondering if I need pull ups on the IC side of the voltage translator on this breakout board as some googling suggests. This would make this breakout board pretty useless if you are not using SPI to communicate with the device, which would not require any pull ups. Anyways this smells like the voltage converter is misbehaving. Anyone have experience with this board using I2C or some advice for troubleshooting this issue?
Hello.
What device are you trying to use to control the VL53L8CX? Can you post some pictures of your setup and let us know if there are any other devices on the I²C bus?
The behavior you are describing sounds consistent with the level shifter on the VL53L8CX carrier having trouble. As we note on the product page, the level shifter on this board is more sensitive to external loads than the circuit we typically use, so we recommend taking extra care to keep connected communication wires short (ideally under 3 inches or 8 cm) and limit other devices on the same I²C or SPI bus. Can you try testing the VL53L8CX with short connections by itself on your I²C bus and let us know if that helps?
- Patrick