I have a device that uses I2C to communicate with a small PCA which has an onboard EEPROM with a fixed address and other supporting circuitry. What I want to do is build a small box that has three or more of these small EEPROM PCAs and use a mechanical switch to select one at a time.
I know I can tie the ground and 3.3v supply to all the PCAs commonly and switch the SDA and SCL lines with a 2-pole switch, but to simplify it a bit more, would it work if I tie all of the SDA lines together and use the switch to tie the master SCL to one of the slave EEPROM PCAs?
Would it make a difference if I tie all the SCL lines together and switch the SDA line to one of the slave PCAs?
... Or am I stuck having to switch both the SDA and SCL lines to select a slave PCA?
I know I can experiment and maybe either option would work but I would rather be sure it's not going to bite me on the backside later. I just want to be sure. Later I may opt to use relays or something else (an I2C multiplexer IC?) to perform the same job but I need to use a switch for now.
Thanks for any help or advice!
