Variable configuration accounting machine with automatic identification of the number and type of connected peripheral units

摘要

A variable configuration accounting machine having a central processor unit (CPU) of an LSI (Large Scale Integration) microprocessor type and a plurality of peripheral units selectively connectable to the CPU which gives a selected configuration to the machine. The CPU is connected to a pair of memories. The first memory stores instructions and data, and the second memory stores microprograms. The capacity of both memories is variable according to the number and type of the peripheral units connected to the CPU for a given configuration of the machine. In the second memory is permanently stored an initialization microprogram that, when activated by the operator, automatically causes the identification by the CPU of the number and type of peripheral units connected to the CPU. Moreover, the initialization microprogram controls the CPU to define a reserved zone in the first memory not accessible to the instructions and accessible to the CPU as controlled by the microprograms, for storing data relating to the execution of the instructions and obtaining the maximum of the first memory for storing programs by defining the size of the reserved zone as a function of the number and type of the peripheral units identified.