LeizaR:
hi guys, i have connected 3 arduinos and one rtc, my question is, how do i set the master? i searched on internet but there is nothing, is the master the one with the pullup resistor? or is the one which join with no address (wire.begin()i want to set the rtc module as the clock, or one specific arduino, please help
I think the documentation is pretty clear here:
"address: the 7-bit slave address (optional); if not specified, join the bus as a master."
You have a nice starting point in the example of two arduinos communicating with each other:
https://www.arduino.cc/en/Tutorial/MasterReader
https://www.arduino.cc/en/Tutorial/MasterWriter