| 摘要 |
PURPOSE:To execute the titled microcomputer at the same speed as a usual operation mode by selecting a special operation mode by an operation mode control means, writing an instruction of a test program, etc. in a programmable read only memory, and thereafter, reading out its instruction. CONSTITUTION:In order to operate by a test mode, a signal is inputted to an input terminal 3 from the outside, and an operation mode control means 14 is set to a test mode. As a result, the control means supplies its output signal to a program counter 12 and a prom 17, inputs a parallel instruction of a test program supplied to an input terminal 1 and writes it in the PROM 17. When write of the test program is all ended, the control means 14 reads out an instruction in the PROM 17 by its output signal, and supplies it to an instruction register 10 and an instruction decoder 11. In such a case, by the program counter 12, the instruction in its PROM 17 is read out successively to the instruction register 10, decoded by the instruction decoder 11 and the test program is executed. In such a case, a read-out speed of the PROM 17 does not require a time to access an external memory, therefore, it can be designed on equal terms with a read-out speed of a mask ROM 16. |
