Browse Prior Art Database

Personal Computer With Dual System Bus

IP.com Disclosure Number: IPCOM000039773D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Tran, LT: AUTHOR

Abstract

A technique is described whereby a personal computer (PC) is provided with dual system bus circuitry, incorporated into planar circuitry, so that when bus option circuit cards are installed, the PC will provide operational compatibility with both new and existing optional features. The concept provides a smooth transition for operating features designed for existing PCs, so as to be able to function on a more powerful family of PCs. The circuitry provides a high level of integration designed into the primary planar circuitry of the PC and assumes that the required edge connectors for plugging in the family option cards are provided.

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Personal Computer With Dual System Bus

A technique is described whereby a personal computer (PC) is provided with dual system bus circuitry, incorporated into planar circuitry, so that when bus option circuit cards are installed, the PC will provide operational compatibility with both new and existing optional features. The concept provides a smooth transition for operating features designed for existing PCs, so as to be able to function on a more powerful family of PCs. The circuitry provides a high level of integration designed into the primary planar circuitry of the PC and assumes that the required edge connectors for plugging in the family option cards are provided. Designating the older PCs as family 1 and the new PCs as family 2, the circuitry provided is as shown in the figure and consists of three prime elements: Bus circuitry, family 1 and family 2 option feature cards. Family 1 option card is installed into the PCs whenever the user requires family 1 features to function on the new PCs, such as features used in the IBM PC XT. The new PC cannot operate the features available in the new family 2 at the same time as family 1 feature operation is required. Conversely, the family 2 option card is installed whenever the user requires family 2 features to function on the new PCs. The bus circuitry consists of processor 11, which functions as the controller to system bus circuitry and local bus circuitry 12. Proces- sor 11 is typically an Intel 80286 or equivalent. The bus circuitry provides the necessary logic and hooks to support both families of options when either option card is installed. Gate array 13 provides eight distinct functions: 1) Address latch for address 0 to 19, since this is required for family 1 bus. Address 20 to 23 are not provided since it is not required by eit...