| 摘要 |
PURPOSE:To make it possible to check easily a process control code by building a memory part and a method of checking its contents on the same chip and by allowing the memory part to have the process control code and a test code, which are combined. CONSTITUTION:Integrated-circuit device 8 consists of incorporated ROM1, detection circuit 2, holding circuit 3 set by a detection signal, terminal 4 which transfers an output signal from circuit 3, test circuit 5 which controls a test function, and control gates 6 and 7. For example, level ''1'' is written to a test code as to a line where there are odd-numbered levels ''1'' in bits constituting an instruction set to each line of ROM1, so that every line will have even-numbered levels ''1'' set without fail. By a test instruction from circuit 5, code data is read out to circuit 2 at every line of ROM1 and through a comparsion, it is decided whether the number of levels ''1'' is odd or even; when it is odd, an error in memory data is detected and a detection signal is outputted to circuit 3, thereby outputting a signal indicating the existence of the error to terminal 4 for a constant period. |
