| 摘要 |
PURPOSE:To check an ROM chip without using hardware for checking the ROM chip by adding instruction codes for accessing ROMs, chip by chip, successively in a program, and confirming the operation of each ROM chip. CONSTITUTION:An address corresponding to a chip ROM-1 is denoted as A, an address corresponding to a chip ROM-2 is denoted as B, and an address corresponding to a chip ROM-n is denoted as M; and jump instructions for accessing following ROM chips are stored in them successively. The jump instruction to the address is stored in the address A, so a jump to the address B is caused. Thus, respective ROM instructions are executed successively up to an address M, and a jump instruction to the address A is stored in the address M to execute another processing program successively. If some ROM has a defect, its jump instruction is not executed and the program enters a runaway state, so that the operation faulty is detected by a monitoring function. |
