Service manual

ManualsBrandsAlpha Microsystems ManualsComputer equipmentAM-6060

Rev. B02

DSS-10550-00

June 1998

LEVEL7 Non-Maskable Interrupt Debugger

LEVEL7, the non-maskable interrupt debugger, is a utility to examine the status of a locked-up system.

This can be very useful when debugging interrupt level routines or other functions which may appear to

lock the system. You can also set LEVEL7 to trigger on the standard exception vectors.

To use LEVEL7 to debug a “locked” system, you need to emulate a power fail condition by using either

a switch wired to the UPS port on the CPU board, or via front panel control on those systems supporting

that function. Therefore, you can use LEVEL7 to diagnose system lockups only on CPU boards which

have a UPS port, such as the AM-185-50, AM-4000, Eagle 550, and AM-6000, or on CPU boards which

have configurable front panel control of LEVEL7, such as the Eagle 450 and AM-6060. Information on

constructing the necessary switch for invoking LEVEL7, or information on configuring the CPU board

for front panel control of LEVEL7 is at the end of this document.

Using the LEVEL7 debugger preempts any power fail operations usually performed within the

AMOS monitor; therefore it should only be installed during debugging, not as a normal system

utility.

If your CPU does not have a UPS port or front panel LEVEL7 control, you can still use LEVEL7

to debug any condition which causes one of the normal exception vectors by using the /E or /T

switch, described below.

LEVEL7 is user-extensible via custom overlays, several of which are included. Further information on

programming these overlays is covered later in this document. If you develop your own overlay, and

want it to be included, please submit it with source and instructions to Alpha Microsystems. The overlay

will become property of Alpha Microsystems if included with LEVEL7; no compensation will be given

to the author.

LEVEL7 RELEASE FILES

As of release 1.0(116), the LEVEL7 debugger consists of the following files:

LEVEL7.SYS Main debugger module

GOL7.LIT Program to execute the debugger manually

JCB.L7O Overlay to display job control blocks

TCB.L7O Overlay to display terminal control blocks

DDB.L7O Overlay to display dataset driver blocks

MAP.L7O Overlay to display memory modules

SMEM.L7O Overlay to display shared memory area

DISASM.L7O Overlay to disassemble 680x0 instructions

IDENT.L7O Overlay to identify memory areas

EXAMPL.M68 Example overlay source file

L7OSYM.M68 Symbol file for developing new overlays

Summary of content (9 pages)

PAGE 1
DSS-10550-00 June 1998 LEVEL7 Non-Maskable Interrupt Debugger LEVEL7, the non-maskable interrupt debugger, is a utility to examine the status of a locked-up system. This can be very useful when debugging interrupt level routines or other functions which may appear to lock the system. You can also set LEVEL7 to trigger on the standard exception vectors.
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Page 2 LEVEL7 Non-Maskable Interrupt Debugger INSTALLING LEVEL7 Place the files LEVEL7.SYS and GOL7.LIT in DSK0:[1,4] and all overlays (*.L7O) in DSK0:[7,0]. The source files are needed only if you plan on creating your own overlays. You may install them anywhere; DSK0:[7,7] is normally a good choice. In your system initialization file (always edit a copy of the file, not the original), locate the SYSTEM statements. Before the final SYSTEM statement, add this statement: SYSTEM LEVEL7.
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LEVEL7 Non-Maskable Interrupt Debugger Page 3 LEVEL7 outputs at 19200 baud only. The peripheral attached to CPU port #0 must be set to 19200 baud or the debugger’s output will be unreadable. ***** Level 7 Interrupt Debugger ***** (activated by XXXXXX exception) ------------------------------------------------------------Primary Functions: 1) Exit Level 7 Handler 2) Show Stacked Registers 3) Examine/Modify Location 4) Show System Comm.
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Page 4 LEVEL7 Non-Maskable Interrupt Debugger Examine/Modify Location This option lets you read or write a single memory location. After you select this option you will be asked for the address, then for the size of the read/write to perform. This sequence will repeat endlessly. Press CTRL /C to return to the Main Menu. Show System Comm. Area This option displays the system communication area at 0x400, one page at a time. Press want to abort the listing prior to the end.
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LEVEL7 Non-Maskable Interrupt Debugger Page 5 Display Memory Modules This option lets you display memory module information in system memory, user memory, or starting from a selected address. LEVEL7 asks for the area you want to display. It then lists memory modules one page at a time. If any of the stacked address registers contain a value within the listed module they are displayed to the right of the screen. To exit prior to the end of the modules, press CTRL /C.
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Page 6 LEVEL7 Non-Maskable Interrupt Debugger Support Functions We provide the following macros, which interface to internal LEVEL7 routines to provide for I/O and common conversions: CHROUT Outputs a character to the terminal. The character should be placed in D1. STROUT adr Outputs a string to the terminal. adr is the address register or label where the string is located. STROUT behaves like the TTYL monitor call; it does NOT handle immediate strings like the TYPE monitor call.
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LEVEL7 Non-Maskable Interrupt Debugger Page 7 EXAMPL.M68 Example Overlay LEVEL7 includes source code for an example overlay file. By examining this and using it as a template you will be able to understand the requirements of LEVEL7 overlays: ; EXAMPL - Example LEVEL7 overlay source - does nothing special VMAJOR VMINOR VSUB VEDIT VWHO SEARCH SEARCH COPY OBJNAM SYS SYSSYM L7OSYM .L7O RADIX 16 = = = = = 1 0 0 100.
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Page 8 LEVEL7 Non-Maskable Interrupt Debugger BYBY: BYTE ASCIZ BYTE EVEN ^H0D,^H0A "Goodbye, returning to main menu..." ^H0D,^H0A,0 END Macros and header offsets for LEVEL7 overlays are contained in the file L7OSYM.M68, which is COPYed into the program as it is assembled. The extension of the object module should be .L7O, which is set by the OBJNAM statement in the example code above.
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LEVEL7 Non-Maskable Interrupt Debugger Page 9 UPS PORT WIRING OR FRONT PANEL LEVEL7 CONTROL Several Alpha Microsystems computer systems include an external UPS port which can be used to generate a power fail condition which will allow LEVEL7 to interrogate “locked” systems.