SINGLE-CHIP MICROCOMPUTER

In an evaluation single-chip microcomputer which includes circuit elements connected to an internal bus and capable of storing data or of arithmetic operation, the contents of the circuit elements being required to be known outside of the microcomputer, a control circuit decodes instructions supplied through the internal bus and produces control signals for controlling the operations of the circuit elements, the data written in each of the circuit elements is transmitted to the internal bus during execution of any one of instructions involving transfer of data into the circuit element, and output terminals are provided for outputting part of the control signals from the control circuit and part of the output signals from the circuit elements through the internal bus, the control signals including write control signals for writing data in the circuit elements.