I think it's hard to ask for help when you are truly confused. I apologize = if this question is poorly worded, I don't have enough knowledge to phrase = it right.
I have carried out circuit analysis on PCBs with CPUs but never designed a = circuit that contained them, I am hoping to change this.
I know there are other lines on CPUs that are involved with a variety of si= gnalling but hopefully it's a safe statement to say that most are either ad= dress lines or digital bus lines.
My question is based on logic such as this:
If there was a CPU with 16 digital lines and 24 address lines and that CPU = was on a board that had two 16 bit memory devices. 8 of the 24 address line= s could be conceptually divided away to create a control bus. The control b= us could activate these devices and others one at a time by enabling them a= nd disabling them through tri-state logic.
If this is correct, I am wondering how Linux is used in the embedded world = were a designer will likely not use X86 and a PCI bus but rather their own = control bus? I am assuming that when Linux is compiled, certain configurati= ons are assumed and lines are allocated based on this. Is there a way to co= mpile Linux so that the number of address lines to access memory can be spe= cified? and lines to access other chips can be used as desired?
So just as an example. If there was a 32 bit CPU, could 16 bits be used to = address devices and 16+ lines be used to form a custom control bus that mig= ht control the state of numerous devices on the board?
Thanks for reading-Patrick