| 摘要 |
PURPOSE:To perform a test or debug routine stored in another address by inserting forcibly a branch instruction into a prescribed address from outside without rewriting the contents of an ROM. CONSTITUTION:The branch instructions which designate branching addresses are set previously to inserting instruction setting parts IIG0-IIGm via key contacts ioo-iok, ilo-ilk, etc. respectively. A branch instruction is delivered to a data line DI from the part IIG0 during execution of a CPU by the coincidence output of an instruction address obtained by a comparator COMPO. The CPU reads a memory MEM in accordance with an address R, for example, which is indicated by the branch instruction and branches the contents of the MEM into instructions to store them to corresponding addresses. Then a program is executed and a comparator COMP1 detects the coincidence of addresses at an address R+m and gives an output to the part IIG1. The branch instruction set at the part IIG1 is supplied to the CPU. Therefore the CPU is reset to the original ROM program and continues execution of instructions. |
