I will begin my research for local robocon competition. My robot team wants to develop a robot with multi microcontroler but i need information about communicating between several microcontrolers like (Master in Slave Out/Slave in Master Out, SP1, I2C). What circuit of encoders that can be used? Thanks for help.

 

I suggest you investigate CAN (Controller Area Network). CAN networks are robust, easy to develop, and supported by multiple vendors. They can be Master/Slave or P2P as you wish.