Re-using pins while still connected to MAX7219 ?

[CuriousOne]

Thanks, that's excellent idea.
I want to attach button which will pull that pin low, when pressed. Since pin is already connected to IC, do I still need pull up resistor?

[Dave]

Why yes you do and don't forget to set the pin as an INPUT.

[CuriousOne]

Thanks, I have another idea.

What I use data pin for beeper? I think I can connect emitter follower thru capacitor to that pin, and buzzer to emitter follower? MAX7219 data speed should be high enough, so buzzer won't play anything while transferring the data?

[pedja089]

Probably you will get audible click on start and stop of data transition, and probably some noise during.
You may implement this
https://www.romanblack.com/shift1.htm

Also you could use SPI port expander, and and use inverted CS signal to drive it. Or some additional transistor circuit to activate buzzer only when LOAD is low.