I am trying to create a modular system that uses UART to broadcast the same data to each microcontroller that gets added to the system. It could have 3 or it could have 10 modules added to the system.
Each PCB module is separated by no more than 1 inch of space (i.e most of the trace length will be running on PCB, the 1 inch is just the jack to make the connection from one PCB to the other). The total length of the system would be about 6ft.
What signal protocol would you suggest that could easily be designed onto a PCB system that is modular? RS485 uses twisted pair, which would be difficult to achieve on a PCB from what I can tell. I was considering hooking up all the Rx's of the "slave" microcontrollers to the Tx of the "master" microcontroller. This would allow instantaneous transmission to all of the slave microcontrollers as needed. I do not intend to use UART to communicate back.
What things should I consider in the design? Could one microcontroller output handle the inputs of up to 10-15 microcontrollers? Will I need to add signal boosters?
It is important to clarify that these devices will be modular, so virtually identical. I can't have some components on boards 5-6 that aren't on boards 7-8 for example. The speed I hope to transmit at is ideally 1Mbps.