Buses

Data Busses

Computers are made of:

  • Processor
  • Memory
  • Data and IO

But how do we go between them? DATA BUSSES! (Well, also control and address buses, I guess).

Busses have a width (how much data can be on them at a time e.g. 16bit) and a clock speed (how often data can be transferred on them).

Data bus = bi-directional. Address bus = uni-directional (from the CPU).

Timing

CPU has to do the timings to ensure reads and writes and other things happen on time. It has a clock! Often IO devices have their own clocks too.

CPU is faster than IO so we have to synch up! Either we can software do it (put a delay in yo but that can be dodge and is a waste of time) or we can do it with hardware (wastes CPU time, but not as much cause it can do other things too)