What Nucleo L476rg GPIO output mode should be used, to appropriately drive the I/O PC13 (i.e., pin connected to B1 User push-button) of another L476rg

[GBumi.1]

I have need to output from a Nucleo L476rg to pin PC13 of another Nucleo L476rg, (i.e., to. the B1 USER push-button)

Reason for input to this pin (which is connected to the blue USER push-button) is simply that all of the second L476rg's other pins are used up by previous programming and shields, and to rewrite the code to free up pins is not any easy task. [I'm new to the use of ST microcontrollers.]

In going through the RM0351 Reference manual, the GPIO output mode can be set to one of three modes (Section 8.2 GPIO main features:(

• Output states: push-pull or open drain + pull-up/down

Which of these modes is appropriate to drive pin PC13 of another L476rg?

[Tesla DeLorean]

If you remove SB17 use Push-Pull, otherwise use Open Drain.

Common the grounds.

PC13 is in the low power domain, it doesn't have high drive current.