Read-only memory and controller using same memory

Abstract

Abstract PURPOSE:To reduce the whole of the program capacity by providing a ROM where program codes independent of one another are stored and a dual port ROM, where a common program code is stored, for two or more CPUs. CONSTITUTION:ROMA and ROMB where program codes independent of each other are individually connected to CPUA and CPUB, and a dual port DPROM where the program code shared between them is stored is connected to them. When power is supplied to a controller, CPUs are started independently of each other, and the CPUA executes the processing in accordance with program codes read out of the ROMA and the A port side of the DPROM, and the CPUB executes the processing in accordance with program codes read out of the CPUB and the B port side of the DPROM. Consequently, the program independent of hardware is read out of the common ROM. Thus, the whole of the program capacity is reduced to improve the space efficiency.

Inventors

• 👤 Arata Umeda
• 👤 Toshiya Tagawa

Bibliographic Details