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Interrupt Controller Diagnostic Wrap Arrangement

IP.com Disclosure Number: IPCOM000038603D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Arroyo, RX: AUTHOR

Abstract

The figure illustrates a software-generated interrupt capability that is employed to functionally test an Interrupt Controller (I.C.). This allows the system software to test the I.C. in a stand-alone environment before proceeding to test the I/O devices. This particular implementation is designed to 8 interrupt levels. However, if more than 8 or less than 8 interrupt levels are present in a system, then the Diagnostic Interrupt Register is expanded or reduced the corresponding amount. The 8 outputs of the Diagnostic Interrupt Register serve as alternate interrupt request sources. These alternate interrupt request sources are selected by the software by toggling the DIAG MODE line. If the DIAG MODE signal is on, the alternate interrupt request sources are selected.

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Interrupt Controller Diagnostic Wrap Arrangement

The figure illustrates a software-generated interrupt capability that is employed to functionally test an Interrupt Controller (I.C.). This allows the system software to test the I.C. in a stand-alone environment before proceeding to test the I/O devices. This particular implementation is designed to 8 interrupt levels. However, if more than 8 or less than 8 interrupt levels are present in a system, then the Diagnostic Interrupt Register is expanded or reduced the corresponding amount. The 8 outputs of the Diagnostic Interrupt Register serve as alternate interrupt request sources. These alternate interrupt request sources are selected by the software by toggling the DIAG MODE line. If the DIAG MODE signal is on, the alternate interrupt request sources are selected. If DIAG MODE is off, the normal interrupt request lines are input to the Interrupt Controller. The DIAG MODE select line is controlled by software via an I/O register bit. The SELECTOR block 11 is simply an 8-wide 2 to 1 multiplexer with the select line common for all 8 multiplexers. Testing of the Interrupt Controller begins by the software writing an I/O register to set the DIAG MODE signal. This will switch the interrupt request lines to the outputs of the Diagnostic Interrupt Register. When the switch occurs, an interrupt may inadvertently be generated. This requires that the I.C. be re-initialized. To simulate an interrupt request 0, the software pe...