binarygod:
Answer/Question on your first paragraph:see attachment!
so if I connect the switch like in the attachment, I can to a hardware reset with the uC AND with the switch if I understood well?
Correct!
Answer/Question on your second paragraph:
I think I missunderstood you! you meant with "to send 3 commands for 3 chips" that when I send data to the first driver I have to send first his adress and then all HIS registers (with his own Shutdown register) with THEIR specific bits, then when I send data to the second driver I have to send first his adress and then his registers (with his own Shutdown register) etc?
You don't HAVE to send all the data to each chip to reset it...you just need to write to the Shutdown register.
In the end I have three methods to reset them??? :
software with their own register, and hardware with a switch & with the uC?
Yep!