Computer system with system ROM including serial-access PROM coupled to an auto-configuring memory controller and method of shadowing BIOS code from PROM

摘要

A computer system having a processor is provided with a memory controller serially coupled to a serial-access programmable read-only-memory ROM (PROM) through a serial PROM interface of the controller. A random-access memory controller randomly accesses the BIOS code in the serial PROM during power-up of the computer system in response to read requests from the CPU. If the memory controller cannot immediately process the read requests from the CPU, the controller creates wait states for the CPU. An auto-configuring memory controller sequentially accesses the entire BIOS code in the serial PROM during power-up and prior to the running of the CPU and copies it to a portion of base memory, eliminating random accesses to the PROM.