Abstract:
An electronic calculator system of the type having a keyboard input and a visual display is implemented in MOS/LSI semiconductor chips having a data memory, an arithmetic unit, a read-only-memory for storing instruction words, and control circuitry for operating the system in response to keyboard inputs by selecting addresses for instructions from the read-only-memory, all of which is located in monolithic semiconductor units. A technique is provided for turning off the display after a selected time period by holding an instruction word in an instruction register while repeatedly incrementing an address register for the ROM until it overflows, then branching to an address defined in such instruction word. This is repeated until the selected time period is reached.