Browse Prior Art Database

Wrap Circuit on Cartridge

IP.com Disclosure Number: IPCOM000034273D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Imoto, N: AUTHOR [+2]

Abstract

This article describes a method to test the connection of one-way bus. Use of an external cartridge to expand functions of a base logic card has become a popular approach. In an attempt to ensure a connection between the base logic card and the cartridge, the connection of the two-way bus can easily be checked (e.g., data bus) by using a read/write operation of a microprocessor. However, for the connection of one-way bus (e.g., a higher address bus to be connected to a decoder on the cartridge), there is no good method to check it. Fig. 1 shows an embodiment of a cartridge associated with a base logic card. The cartridge includes wrap test arrangements for checking the connection of a higher address bus. Fig. 2 shows a test flow using the test arrangements.

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Wrap Circuit on Cartridge

This article describes a method to test the connection of one-way bus. Use of an external cartridge to expand functions of a base logic card has become a popular approach. In an attempt to ensure a connection between the base logic card and the cartridge, the connection of the two-way bus can easily be checked (e.g., data bus) by using a read/write operation of a microprocessor. However, for the connection of one-way bus (e.g., a higher address bus to be connected to a decoder on the cartridge), there is no good method to check it. Fig. 1 shows an embodiment of a cartridge associated with a base logic card. The cartridge includes wrap test arrangements for checking the connection of a higher address bus. Fig. 2 shows a test flow using the test arrangements.

(Image Omitted)

In the test operation, a particular address signal comprising four address bits S3- S0 is transferred from the base logic card to the cartridge through the higher address bus. If this address bus is properly connected to a corresponding bus in the cartridge, the particular address signal is properly received by a decoder in the cartridge. Then, the decoder enables a gate to pass the address signal to a data bus as a signal including four bits D3-D0, so that the latter signal is returned to the base logic card. By comparing the transmitted address signal and the received signal, the connection status of the higher address bus is determined. By using this method, a PC-ba...