SEMICONDUCTOR INTEGRATED CIRCUIT FOR DATA PROCESSING

摘要

PURPOSE:To minimize the correction of hardware and to increase the memory space of an internal memory by setting address data for expanding the address space to part of a control register or its free bits. CONSTITUTION:Part of the control register 17 or free bits are assigned for high-order address bit addition for internal data memory space expansion, and the high-order address bits are supplied to a data memory 7 and is also outputted to outside through an address output buffer 18. The addressing in the expanded space is carried out according to the setting contents of the high- order address bits of the control register 17 and address signals outputted from an address counter 11 and an instruction register 5, so the internal memory space is expanded without correcting for altering the hardware greatly and the internal memory function is expanded externally.