Electronic circuit for connecting a processor to a high-capacity memory

The electronic circuit connects a processor (20) to a high-capacity memory (21) of 1 Megabyte. The processor (20) may be of the 8 bit type, with a 16 bit address bus (AO-A15). The memory is subdivided into 256 segments each having a capacity of 4 Kbytes which can be directly addressed by the processor by means of 12 (A0-A11) of the 16 lines of the address bus. An auxiliary RAM (30) is interposed between the processor (20) and the 1 Mbyte memory (21) and comprises sixteen 8 bit registers (RO-R15), which can be addressed by means of the other four lines (A12-A15) of the address bus. By means of the 8 bit data bus (DO-D7), the 16 registers of the RAM (30) store the numbers of those 16 segments out of the 256 segments of the 1 Mbyte memory, which from time to time are connected to the processor. In this way the processor (20), while being able to address only 64 Kbytes of memory at a time, has the whole of the 1 Mbyte memory available. The circuit can be applied to data processing and word processing units and electronic typewriters.