VL6180X Bus Lockup

[Tashfique]

In our design the Proximity sensor is locking up in 90% of the boards.

It ranges properly on its own.

But when added to the bus, rest of the sensors function properly and only VL6180X is locking up. This is an ongoing issue.In the boards where its failing ... if we don't talk to the device, other sensors work properly. As soon as we try to initialize the proximity, it will lock up. I have checked the bus rise and fall times .. around 200 to 400 ns. Why is this chip so sensitive? Do you guys have any recommendation. We need to go into production asap so any suggestion will be helpful.

Also, found out that if the Proximity sensor is run in continuous mode, it needs to be reset using GPIO 0 on the next power up. Right after powerup. or else it gets stuck ranging.

If you require the schematic and the list of sensors attached to the bus, please let me know.

Thanks,

Tashfique

[John E KVAM]

This is a bit of a guess - but an educated one. The only problem we have with this chip is an extreme sensitivity to noise on the reset line.

Put a really  big pull up on that or a cap near the device, or I had one customer change the XSHUT on his MCU to an input to reduce the change of a reset.

And a reset would look a lot like a hang. It's even possible to only partially reset the chip with a small glitch - where the I2C works, but the chip doesn't.

Give that a try and report back. I'm hopeful it will fix you right up.