universal memory card - 64 K RAM and/or EPROM with battery backup

universal memory card elektor march 1983 The continuing development of "bigger" memory ICs obliges us to develop new, versatile and more powerful RAM/EPROM cards at regular intervals. The universal memory card described here is suitable for most microcomputers with an 8-bit data bus and it can accept up to 64 K RAM or EPROM. A combination of both types of memory is also possible. If CMOS RAMs are utilised, a backup battery will protect the memory contents for a considerable time, thus preventing the data from being lost when the computer is switched off (power-down). 64 K RAM and/or EPROM with battery backup The computer memory In general, a microcomputer system contains the sections shown in figure 1. The micro- processor chip contains various registers, the program counter and the arithmetic and logic unit (ALU); the clock generator may also be included on-chip in certain micro- processor types. The other main section is the memory, usually consisting of both RAM and ROM or (E)P...