VL53L1X - XSHUT pin.

[JarJar1]

Hello,

I'm trying to use the VL53L1X sensor with an Icarus board.

With a classic connection, the sensor works and the results are ok.

Now I would like to manage the sensor by the XSHUT pin.

Through the documents and comments, it's not very clear (for me) if the XSHUT pin allows powering instead of VIN?

If so, when I initialize this pin to HIGH, and then i reset the sensor, I can no longer measure.

Anyone have an idea?

Thanks !

[John E KVAM]

the XSHUT pin should work like an on/off switch. The lamp is still plugged in, but switched off. Lowering the pin and bringing it back up should reboot the sensor and you are ready to go.

The only thing I can think of is that the sensor is not as fast as your MCU, so if you toggled the pin without a few milliseconds between off and on, you might just put the sensor into an unusable state.

(I always use 10ms, but I'm not in a hurry.)

VIN provides the power, XSHUT is the on/off switch. You need both. And the order should not matter.

[JarJar1]

Thanks for the clarification John!

I thought with the XSHUT pin I could completely shut off the sensor.

On my board, I attempted to electronically or physically cut power to the sensor, and if I leave the SDA & SCL pins connected, it continues to draw (about 15uA).

Is this behavior on the card side (because of the 3.3V on the SCA & SDL pins) or on the sensor side?

Disabling i2c doesn't seem to have any effect...

[JarJar1]

Hi @John E KVAM​ ,

It seems that my problem comes from the current drain on i2c (10uA).

If I understand the documentation correctly, when there is no current, but the SDA/SCL pins are connected, the sensor draws 10uA.

Whereas if there is current, it drops to 0.15uA?

Is there a solution to avoid this current leakage ?

Thanks

[John E KVAM]

Philips invented the I2C bus long ago and NXP bought Philips, so NXP has the best documentation on that bus. A careful study of what documentation they have will help.

I googled "I2C current drain" and there were lots of helpful articles.

But while idle, the SDA and SCL lines are pulled high. When clocking a bit, the MCU or the sensor pulls the the line low an the bit is clocked on the rising edge.

The strength of the pull-up that has to be overcome then is important to how much that bus requires. A good strong pull-up will make the transitions faster, but at the cost of power. It's always that tradeoff.

I'd suggest really digging into how the I2C bus works, and you will find a set up that works for you.

• john