gpio alt mode conflict

[cleverca22]

what happens if you set 2 gpio pins to conflicting alt modes?

for example, setting gpio0 to alt0(SDA0) but also setting gpio28 to alto(SDA0)

would the internal buffers within the mux array begin to fight eachother, or is there some safety to prevent damage in such a situation?

[6by9]

what happens if you set 2 gpio pins to conflicting alt modes?

for example, setting gpio0 to alt0(SDA0) but also setting gpio28 to alto(SDA0)

would the internal buffers within the mux array begin to fight eachother, or is there some safety to prevent damage in such a situation?

Generally you end up with nothing.
I don't know the exact internal logic, but I suspect it's an or on the input path, so with I2C pullups it always sees a 1, and therefore no ACKs.

[cleverca22]

ah, and that kind of feels like it makes the most sense, design-wise

the mux is just a giant matrix of tri-state buffers, and then a big OR gate to combine them all, with an internal (weak) pulldown maybe after each tristate

sounds like its probably safe to cause a conflict on purpose and confirm things exactly