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Microcode Analysis Technique for Printer

IP.com Disclosure Number: IPCOM000061111D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 69K

Publishing Venue

IBM

Related People

DiIorio, RW: AUTHOR [+3]

Abstract

The inclusion of basic microcode analysis functions in an operator- selectable utility program for a printer decreases the need for diagnostic instruments and enables remote diagnosis via telephone. An analytical utility program can be made selectable at the operator panel of a printer having a keyboard, indicator lights and limited alphanumeric display. Once selected, the utility program redefines the functions of the keys. An example of functions available in a microcode diagnostic program are: Display and Alter Memory Scan Memory for Unique Data String Display and Alter Diskette Instruction Address Match Instruction Address Match with Data Store Instruction Address Match with Extended Data Log Supporting utility code runs at low interrupt priority so normal printer functions are not disturbed.

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Microcode Analysis Technique for Printer

The inclusion of basic microcode analysis functions in an operator- selectable utility program for a printer decreases the need for diagnostic instruments and enables remote diagnosis via telephone. An analytical utility program can be made selectable at the operator panel of a printer having a keyboard, indicator lights and limited alphanumeric display. Once selected, the utility program redefines the functions of the keys. An example of functions available in a microcode diagnostic program are: Display and Alter Memory Scan Memory for Unique Data String Display and Alter Diskette Instruction Address Match Instruction Address Match with Data Store Instruction Address Match with Extended Data Log Supporting utility code runs at low interrupt priority so normal printer functions are not disturbed. Main and support microprocessors each have their own code with the main microprocessor handling the keyboard input and display functions, user and utility error conditions, support microprocessor communications, and applicable utility functions, while the support microprocessor handles its appropriate functions and code for communicating with the main microprocessor. Display and Alter memory function uses normal load and store instructions of each microprocessor to read and alter both data and instructions in random-access memory. A similar technique is used for Scan Memory for Unique Data String to compare contents of memory with a user- specified data string. With Display and Alter Diskette the user can read and alter the printer microcode and control data on the diskette. The Instruction Address Match functions use the microprocessor ability to detect invalid instruction op code and generate a high, Level O interrupt. This interrupt is then serviced by a software routine. The technique used when the function is invoked is to save the instruction at the address match location and store an invalid op code at this location. With address matching, the hardware will determine op code invalidity and generate a Level O interrupt to determine whether the analysis utility program is active. If not active, the invalid op code is processed normally. If the utility program is active, the previously saved valid instruction is stored at the address match location, a flag is set indicating the match, and an indica...