SINGLE CHIP MICROCOMPUTER WITH USER DESIGNED CIRCUIT

摘要

A single chip microcomputer consists of a single chip microcomputer core, an external bus interface circuit, an external bus logic circuit and a bus interface. To asynchronously access externally from the single chip microcomputer core, the external bus interface circuit generates an asynchronous access control signal externally based on the access control signal from the single chip microcomputer core. The internal bus interconnects the single chip microcomputer core and external bus interface circuits, and the logic circuits become asynchronously accessible from and to the single chip microcomputer core. The bus interface circuit is connected to the internal bus and generates an asynchronous access control signal to the logic circuit based on the access control signal input through the internal bus. Even when the user logic unit is designed with an operation clock that is independent of the operation clock of a single chip microcomputer, the function of the user logic unit is not limited to any significant limitations, and the number of steps associated with preparing the user logic test form is reduced.