I have a fairly general problem in understanding, I guess, "bus systems": Take the following scenario: We aim to create a motherboard-type of board, it shall use some kind of CPU that is able (assuming the right software is supplied) to control (write) and sense (read) from several periphery devices like sensors (thermo sensors etc.) and actuators (like stepper motors).
Obviously we cannot wire each component directly to the CPU. Instead we use a system bus to connect things together. We can use Encoding and Decoding (Multiplexing) to address certain devices and send data to them or read a certain register value.
But how does the electronic implementation detail look like? Decoding and Encoding should require some sort of additional processor that en-/decodes data according to the bus specification including timing requirements, right? But this in turn means that we simply connect several processors together using a common interface language, i.e. protocol. Moreover, in the end, each periphery device class has a dedicated processor, for example a USB serializer.
Glad for any hints and clarifications! Thanks!