| 摘要 |
PURPOSE:To check up to which instruction the circuit is operated normally by interrupting the operation of a device to be tested when a program testing the device to be tested is stored in an ROM and a test instruction is proceeded up to a predetermined address on the ROM. CONSTITUTION:In confirming whether or not instructions until an address [alpha+n] are executed correctly by the device 3 to be tested, a part of a program stored in an ROM2 is replaced into an instruction, e.g., [FF], the address [alpha+n] in set to an address setting circuit 4 and a command to be returned to an address [alpha] is given to a data setting circuit 7. When a CPU1 outputs the [alpha+n] to an address bus 10, a data read from the ROM2 is blocked for its output to a bus 9 and the data [FF] set in advance to the data setting circuit 7 is given on the bus 9. The normal operation of the device to be tested until the [alpha+n] is confirmed in this way. |
