The Z80 Sync Bus Controller

The component at location 6D will be either an NVC285 custom integrated circuit or a small printed circuit board with TTL chips. This is the Z80 SYNC bus controller. Its purpose is to control the passage of data between the CPU data bus and the DB (buffered data) bus. Information can pass through component 6D from the CPU data bus to the DB bus or from the DB bus to the CPU. When a component can pass data in either direction it is called bidirectional. To see how this is accomplished look at...