I know that I2C devices are supposed to have unique addresses when used. What if I still use multiple devices with the same address, what can go wrong? Let me describe the situation:
I have multiple digital capacitors (NCD2400M by IXYS) and I would be using them so, that I always send the same command to every chip. I have no need of reading anything from those, which is the reason I was thinking why should I bother multiplexing my I2C line. I have no reason to identify them, only commanding. For the commanding I use Arduino (Nano currently, might change to some other Arduino model).
I have already tried commanding them simultaneously and it works like a charm. I tried so that I connected SDA and SCL of four chips and used RC circuit and square wave to check the rise time to verify that every chip indeed changes their capacitance.
However, I'm new to I2C protocol and I'm not yet aware of every detail. I guess there could be issues when one of the chips fail? Can I assume in this case that nothing goes wrong with the ACK/NACK bit since the chips are "identical"?
EDIT: After using correct keywords for searching I found this previously asked question. Based on that I now understand at least there would be a problem when only one of the chips tries to send NACK bit.