Computer system with system ROM including serial-access PROM coupled to an auto-configuring memory controller and method of shadowing BIOS code from PROM
First Claim
1. A computer system comprising:
- a processor;
an internal serial-access programmable read-only-memory (PROM) for storing BIOS code;
a memory controller coupled to said processor and serially and directly coupled to said PROM for addressing said PROM and for loading the BIOS code from said PROM comprising;
a serial PROM interface coupling said memory controller and said serial PROM allowing communication between said controller and said PROM; and
serial PROM interface control logic for controlling said serial PROM interface; and
an internal parallel-access programmable read-only-memory coupled to the memory controller.
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Accused Products
Abstract
A computer system having a processor is provided with a memory controller serially coupled to a serial-access programmable ROM (PROM) through the serial PROM interface of the controller. The 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. The 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.
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Citations
29 Claims
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1. A computer system comprising:
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a processor; an internal serial-access programmable read-only-memory (PROM) for storing BIOS code; a memory controller coupled to said processor and serially and directly coupled to said PROM for addressing said PROM and for loading the BIOS code from said PROM comprising; a serial PROM interface coupling said memory controller and said serial PROM allowing communication between said controller and said PROM; and serial PROM interface control logic for controlling said serial PROM interface; and an internal parallel-access programmable read-only-memory coupled to the memory controller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A random-access memory controller coupled to a processor of a computer system, said controller further directly and serially coupled to a internal serial-access programmable read-only-memory and coupled to an internal parallel-access programmable read-only-memory, comprising:
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wait state logic for asserting wait states into the cycles of a processor; PROM address mapping logic for mapping said processor addresses to PROM addresses; a serial PROM interface coupling a memory controller and an internal serial PROM allowing communication between said memory controller and said internal serial PROM; and serial PROM interface control logic for controlling said serial PROM interface. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A computer system adapted for loading BIOS code from an internal serial-access programmable read-only-memory (PROM), comprising:
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a processor; a internal serial-access PROM to store BIOS code; and a memory controller coupled to the processor and directly and serially coupled to the internal serial-access PROM, comprising; PROM addressing mapping logic to map between processor addresses and PROM addresses; a serial PROM interface to allow communication between the memory controller and the internal serial-access PROM; and a serial PROM interface control logic to control the serial PROM interface; and an internal parallel-access programmable read-only-memory coupled to the memory controller. - View Dependent Claims (28, 29)
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Specification