Can arduino atto read pwm?

it's all in the subject

Define "PWM".
Define "read"

It's all in the detail.

In my system, I have a liquid level sensor that outputs= 5V 50 Hz PWM 0% - 1100us 100% - 1900us.

I have a rpi zero as the center of my system, and I need to feed this information to it, so it can trigger commands. I have a weight limit, so I was thinking of inputting the liquid level sensor to arduino atto, get the percentage value and send to rpi via I2C

sorry for not detailing @TheMemberFormerlyKnownAsAWOL , I have the habit of oversimplifying

So you're saying that the 0 to 100% range is covered by a pulse width of 800us?
You should be able to do this fairly simply with pulseIn, but probably a little more accurately using the timer capture interrupt.