Browse Prior Art Database

Method of Executing Manufacturing ROM Code Without Removing System Roms

IP.com Disclosure Number: IPCOM000037214D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Arroyo, RX: AUTHOR [+4]

Abstract

Disclosed is a method to allow manufacturing ROM code to replace system ROMs without requiring their removal. This method relates to a PS/2 computer which has ROMs on the system planar containing the power-on self test (POST) and the basic input/output system (BIOS). Upon initial power-up, the system is controlled by the code in these ROMs.

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Method of Executing Manufacturing ROM Code Without Removing System Roms

Disclosed is a method to allow manufacturing ROM code to replace system ROMs without requiring their removal. This method relates to a PS/2 computer which has ROMs on the system planar containing the power-on self test (POST) and the basic input/output system (BIOS). Upon initial power-up, the system is controlled by the code in these ROMs.

In manufacturing, it is desirable to use different start-up code to aid in the isolation of manufacturing defects. However, the process of removing the system ROMs from their sockets, inserting the manufacturing ROMs, performing the tests, and finally replacing the system ROMs is time consuming, requires operator assistance, and introduces the possibility for bent pins, ROMs plugged in backwards, shipment of the wrong ROMs, etc.

The test method developed for this computer system allows manufacturing code to be executed during system initialization without requiring the removal of the planar ROMs. It also allows the manufacturing ROM to drive the same data bus as the planar ROM, minimizing the special test hardware requirements.

The normal planar ROM access involves two custom LSI chips that were developed for this system. The memory controller chip generates a ROM chip enable signal. The processor support chip generates a MICRO CHANNEL* bus cycle when it detects an active ROM chip enable signal. The ROM output enable input is then controlled by the MICRO C...