Central processing unit

A central processing unit having: (A) a microprocessor; (B) a main memory; (C) a microprocessor interface. The interface includes: a semiconductor integrated circuit having formed therein: (i) a data rebuffering section disposed in the chip and adapted to couple data from a one of a plurality of data ports to a data port of the microprocessor selectively in accordance with a control signal; and (ii) a main memory interface adapted for coupling to a main memory for the microprocessor, such main memory interface being adapted for coupling to the microprocessor and being coupled to the data rebuffering section for providing control signals to the main memory section for enabling data transfer between the main memory and the microprocessor through the data rebuffering section. A controller is coupled to the data rebuffering section for producing the control signal. The main memory is a selected one of a plurality of memory types each type having a different data transfer protocol and the main memory interface is configured in accordance with the selected one of the plurality of memory types to provide a proper memory protocol to data being transferred between the microprocessor and the main memory through the main memory interface. One main memory type is an SDRAM or a RDRAM.