I like to design a single master, several slave (up to 100) application and looking for a reliable (up to 30meter) multi drop bus. One or two lane is preferred, I will use daisy chain topology therefore USB is not suitable and also it is an overkill.
My data rate is low and intermittent, once every 3-5 sec and probably <10KB. The slaves are not synchronized.
I thought about using RS232 and implement an algo where slave transmits if there is no traffic. (Similar to Ethernet). I prefer something a bit more robust.
Also, current thinking is to wake all slaves when master transmit where all slaves receive the message, they all parse it but the one we targeted takes action. Not very efficient but it would work.