Browse Prior Art Database

Program Debug Tool for Microprocessors

IP.com Disclosure Number: IPCOM000089041D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Kellerman, E: AUTHOR [+2]

Abstract

The present system provides a low cost tool for monitoring program execution on microprocessors. The tool does not require modifications to the microprocessors and does not interfere with the program that is being monitored. It can be constructed from off-the-shelf components at a very low cost.

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Program Debug Tool for Microprocessors

The present system provides a low cost tool for monitoring program execution on microprocessors. The tool does not require modifications to the microprocessors and does not interfere with the program that is being monitored. It can be constructed from off-the-shelf components at a very low cost.

As shown, an External Memory Address (EMA) and an appropriate Strobe are inputs to Compare circuitry together with the Selected Memory Address (SMA) which is normally set by switches. The Compare circuitry drives a Counter/Display which advances whenever the microprocessor accesses the Selected Memory Address. A Counter Reset button is provided. A switched connection is also provided from the Compare circuitry to the Interrupt pin of the microprocessor to stop or execute an Interrupt, handling routing on an address match.

One application of the present device is in a microprocessor system which has a tape I/O program in a read-only memory (ROM). Success or failure of a tape read operation is not indicated until completion of the tape scan. Using the present device, it is possible to monitor the tape read program to determine if it is processing the tape successfully. Since the tape read program is in ROM, it is not possible to modify it to avoid the problem.

Another application is during program debug when it is desirable to interrupt execution of a program without modifying the program itself. The device provides this facility by ge...