MAIN BOARD, SUBSTRATE FOR MEMORY MODULE, AND MEMORY MODULE

摘要

PROBLEM TO BE SOLVED: To provide a controller capable of coping with specification change without redesigning a main board. SOLUTION: A ROM and a RAM are made mountable on one sheet of sub- board, and combined with plural main boards common in use to constitute the controller. The plural sub-boards are prepared in their patterns to cope flexibly with the change in a memory capacity or the like.