Simple computer circuits
In this chapter we look at how a small computer may be constructed using the G80 microprocessor. We begin with the design of the simplest computer, COMP1, which comprises just a G80 microprocessor and a single read-only memory (ROM) chip that stores the program code. This computer is then developed into COMP2, which is the same as COMP1 but with the addition of a single RAM chip. Computer COMP3 has a single ROM chip and two RAM chips. The sequence of events for both memory read and memory write operations are discussed.
Let us assume that the G80 is to be fabricated on a piece of silicon semi conductor. What signals should we bring into the outside world, that is, what is the pin-out