Re-using pins while still connected to MAX7219 ?

[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.