Calculator with constant memory

摘要

A calculator having constant memory utilizing a classical CMOS metal gate process, a low power microcomputer with on-chip and external constant memory capability. Incorporation of a switched negative voltage and a non-switched negative voltage to the appropriate P (-) wells enables the power hungry clocked logic to be turned off while power is maintained on the internal static RAM, on the digit latches, and on the R-lines which connect to both the internal and external RAM. Thus, semi-non-volatile memory (constant memory) capability may be achieved with a low standby current.