XHC-WHB04-4 Python component

sure.
h.fn is output pin of self hal component. "data" structure contains received data from whb device. Fields [2] and [3] are pressed buttons, value 12 means fn button pressed.

on metric inrements are 1mm, 0.1mm, 0.01mm, 0.001mm. On imperial each should be divided by 10 - line 196
can you check with halshow whb inc and axis jog-scale pins? what do they show on your configuration. Show your hal files so I can check.

Sorry let me clarify my question. I don't have a full understanding of the python syntax, yet. I'm trying to understand the a = b == x or c == x syntax. I know what a,b,c, and x are, just not what the equals signs and or mean when combined like that. does it mean that a is true if either b == x or c == x.

If so, why do you have to check both data[2] and data[3]?

yes.

read realpython.com/python-boolean/

whb allows 2 simultaneous keys pressed, it returns the first pressed in [2] and the second in [3] this allows to have alternate key functionality with fn key...

Ok, understand now. So, why do you have to check both data[2] and data[3]?

do a print(data) in line 180 and watch output in terminal while pressing different buttons on the pendant...

I couldn't come up with any combination of button presses that changed data[3], it appears to always be zero.

Also, have you come up with a way to identify button releases? I see the release events happen, but it doesn't appear to identify which button was released.

Release event is identified as data[2]==0

If you want to know which button was released you should first save the state of pressed buttons and compare it with the state in the next iteration of while(1)

What if you had two buttons pressed, and released one. How could you know which one was released?

What are you trying to do?
You can simply save the state of the pin you are interested in and compare it with the value of the said pin in the next iteration.

For a more Pythonic way investigate this:
stackoverflow.com/questions/51885246/cal...ble-change-in-python