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Diagnostic Status for Non-Maskable Interrupt Arbitration

IP.com Disclosure Number: IPCOM000040174D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Dean, ME: AUTHOR [+4]

Abstract

A technique is described whereby a diagnostic status port is provided by the central arbiter for computers using non-maskable interrupt (NMI) arbitration. The concept enables the computer to perform error recovery when an NMI occurs. It allows diagnostics to be performed or enables the operating system program to disconnect a connected device and to advise the user that the device is no longer functioning. (Image Omitted) The NMI subroutine incorporating the diagnostic function is shown in the dotted section of the flow chart. When an NMI is detected, the central arbiter provides status in a port to allow the central processing unit (CPU) to determine the type of error, enabling the CPU to read whether the NMI has occurred due to a bus time-out.

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Diagnostic Status for Non-Maskable Interrupt Arbitration

A technique is described whereby a diagnostic status port is provided by the central arbiter for computers using non-maskable interrupt (NMI) arbitration. The concept enables the computer to perform error recovery when an NMI occurs. It allows diagnostics to be performed or enables the operating system program to disconnect a connected device and to advise the user that the device is no longer functioning.

(Image Omitted)

The NMI subroutine incorporating the diagnostic function is shown in the dotted section of the flow chart. When an NMI is detected, the central arbiter provides status in a port to allow the central processing unit (CPU) to determine the type of error, enabling the CPU to read whether the NMI has occurred due to a bus time-out. As shown in the flow chart, if the time-out bit = 0, the the error was not a bus- master control error, but probably was a data error. If the time-out bit = 1, the last master on the bus caused an error. The value of the arbitration level from the last master is also in the diagnostic port.

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